<?xml version="1.0" encoding="utf-8"?>
<!--Generated by DFIN XBRL Instance Document - http://www.dfinsolutions.com/ - Version R3.0 - on 16-November-2021 [02:13:13] {AM}-->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#CondensedConsolidatedBalanceSheets" roleURI="http://www.definitivehc.com/role/CondensedConsolidatedBalanceSheets" />
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#CondensedConsolidatedStatementsOfOperations" roleURI="http://www.definitivehc.com/role/CondensedConsolidatedStatementsOfOperations" />
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#CondensedConsolidatedStatementsOfComprehensiveLoss" roleURI="http://www.definitivehc.com/role/CondensedConsolidatedStatementsOfComprehensiveLoss" />
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#CondensedConsolidatedStatementsOfCashFlows" roleURI="http://www.definitivehc.com/role/CondensedConsolidatedStatementsOfCashFlows" />
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#BusinessCombinationsScheduleOfConsiderationTransferredInBusinessCombinationDetail" roleURI="http://www.definitivehc.com/role/BusinessCombinationsScheduleOfConsiderationTransferredInBusinessCombinationDetail" />
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#BusinessCombinationsScheduleOfRecognizedAssetsAndLibailitiesPertainingToBusinessCombinationDetail" roleURI="http://www.definitivehc.com/role/BusinessCombinationsScheduleOfRecognizedAssetsAndLibailitiesPertainingToBusinessCombinationDetail" />
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#BusinessCombinationsScheduleOfReconciliationOfPurchasePriceToTheCapitalContributionDetail" roleURI="http://www.definitivehc.com/role/BusinessCombinationsScheduleOfReconciliationOfPurchasePriceToTheCapitalContributionDetail" />
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#RevenueScheduleOfRevenueRemainingPerformanceObligationDetail" roleURI="http://www.definitivehc.com/role/RevenueScheduleOfRevenueRemainingPerformanceObligationDetail" />
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#AccountsReceivableScheduleOfAccountsReceivableDetail" roleURI="http://www.definitivehc.com/role/AccountsReceivableScheduleOfAccountsReceivableDetail" />
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#PropertyAndEquipmentScheduleOfPropertyPlantAndEquipmentDetail" roleURI="http://www.definitivehc.com/role/PropertyAndEquipmentScheduleOfPropertyPlantAndEquipmentDetail" />
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#GoodwillAndIntangibleAssetsScheduleOfCarryingAmountsOfGoodwillAndIntangibleAssetsDetail" roleURI="http://www.definitivehc.com/role/GoodwillAndIntangibleAssetsScheduleOfCarryingAmountsOfGoodwillAndIntangibleAssetsDetail" />
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#GoodwillAndIntangibleAssetsScheduleOfEstimatedIntangibleAmortizationExpenseDetail" roleURI="http://www.definitivehc.com/role/GoodwillAndIntangibleAssetsScheduleOfEstimatedIntangibleAmortizationExpenseDetail" />
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#AccruedExpensesAndOtherCurrentLiabilitiesScheduleOfAccruedExpensesAndOtherCurrentLiabilitiesDetail" roleURI="http://www.definitivehc.com/role/AccruedExpensesAndOtherCurrentLiabilitiesScheduleOfAccruedExpensesAndOtherCurrentLiabilitiesDetail" />
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#CommitmentsAndContingenciesScheduleOfMinimumFutureRentalPaymentsDetail" roleURI="http://www.definitivehc.com/role/CommitmentsAndContingenciesScheduleOfMinimumFutureRentalPaymentsDetail" />
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#CommitmentsAndContingenciesScheduleOfEstimatedAnnualMinimumPurchaseCommitmentsDetail" roleURI="http://www.definitivehc.com/role/CommitmentsAndContingenciesScheduleOfEstimatedAnnualMinimumPurchaseCommitmentsDetail" />
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#LongTermDebtScheduleOfLongTermDebtInstrumentsDetail" roleURI="http://www.definitivehc.com/role/LongTermDebtScheduleOfLongTermDebtInstrumentsDetail" />
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#LongTermDebtScheduleOfFuturePrincipalPaymentsDetail" roleURI="http://www.definitivehc.com/role/LongTermDebtScheduleOfFuturePrincipalPaymentsDetail" />
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#IncomeTaxesScheduleOfReconciliationOfIncomeTaxExpenseDetail" roleURI="http://www.definitivehc.com/role/IncomeTaxesScheduleOfReconciliationOfIncomeTaxExpenseDetail" />
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#IncomeTaxesScheduleOfComponentsOfIncomeTaxProvisionOrBenefitDetail" roleURI="http://www.definitivehc.com/role/IncomeTaxesScheduleOfComponentsOfIncomeTaxProvisionOrBenefitDetail" />
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#IncomeTaxesScheduleOfComponentsOfDeferredTaxAssetsAndLiabilitiesDetail" roleURI="http://www.definitivehc.com/role/IncomeTaxesScheduleOfComponentsOfDeferredTaxAssetsAndLiabilitiesDetail" />
<roleRef xlink:type="simple" xlink:href="dh-20210930.xsd#LossPerShareScheduleOfReconciliationOfEarningsPerShareBasicAndDilutedDetail" roleURI="http://www.definitivehc.com/role/LossPerShareScheduleOfReconciliationOfEarningsPerShareBasicAndDilutedDetail" />
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/AccountsReceivableScheduleOfAccountsReceivableDetail">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsReceivableGrossCurrent" xlink:label="loc_us-gaap_AccountsReceivableGrossCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsReceivableNetCurrent" xlink:to="loc_us-gaap_AccountsReceivableGrossCurrent" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsReceivableNetCurrent" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable" use="optional" order="2" weight="-1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/PropertyAndEquipmentScheduleOfPropertyPlantAndEquipmentDetail">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" use="optional" order="2" weight="-1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/GoodwillAndIntangibleAssetsScheduleOfEstimatedIntangibleAmortizationExpenseDetail">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" use="optional" order="2" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" use="optional" order="3" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" use="optional" order="4" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" use="optional" order="5" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" use="optional" order="6" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/BusinessCombinationsScheduleOfConsiderationTransferredInBusinessCombinationDetail">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesGross" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationConsiderationTransferred1" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesGross" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationConsiderationTransferred1" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable" use="optional" order="2" weight="1" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_BusinessCombinationContingentConsideration" xlink:label="loc_dh_BusinessCombinationContingentConsideration" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationConsiderationTransferred1" xlink:to="loc_dh_BusinessCombinationContingentConsideration" use="optional" order="3" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/CondensedConsolidatedStatementsOfOperations">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossAttributableToParentDiluted" xlink:label="loc_us-gaap_NetIncomeLossAttributableToParentDiluted" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="loc_us-gaap_NonoperatingIncomeExpense" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLossAttributableToParentDiluted" xlink:to="loc_us-gaap_NonoperatingIncomeExpense" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xlink:label="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense" xlink:to="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" use="optional" order="2" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense" xlink:to="loc_us-gaap_InterestExpense" use="optional" order="3" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ExtinguishmentOfDebtGainLossNetOfTax" xlink:label="loc_us-gaap_ExtinguishmentOfDebtGainLossNetOfTax" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense" xlink:to="loc_us-gaap_ExtinguishmentOfDebtGainLossNetOfTax" use="optional" order="4" weight="1" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_NetIncomeLossAttributableToReorganizationTransactions" xlink:label="loc_dh_NetIncomeLossAttributableToReorganizationTransactions" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLossAttributableToParentDiluted" xlink:to="loc_dh_NetIncomeLossAttributableToReorganizationTransactions" use="optional" order="5" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLossAttributableToParentDiluted" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" use="optional" order="6" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLossAttributableToParentDiluted" xlink:to="loc_us-gaap_OperatingIncomeLoss" use="optional" order="7" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaap_GrossProfit" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss" xlink:to="loc_us-gaap_GrossProfit" use="optional" order="8" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization" xlink:label="loc_us-gaap_CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit" xlink:to="loc_us-gaap_CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization" use="optional" order="9" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostOfGoodsAndServicesSoldAmortization" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSoldAmortization" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSoldAmortization" use="optional" order="10" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit" xlink:to="loc_us-gaap_Revenues" use="optional" order="11" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingExpenses" xlink:label="loc_us-gaap_OperatingExpenses" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss" xlink:to="loc_us-gaap_OperatingExpenses" use="optional" order="12" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SellingAndMarketingExpense" xlink:label="loc_us-gaap_SellingAndMarketingExpense" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses" xlink:to="loc_us-gaap_SellingAndMarketingExpense" use="optional" order="13" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense" use="optional" order="14" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense" use="optional" order="15" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DepreciationAndAmortization" xlink:label="loc_us-gaap_DepreciationAndAmortization" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses" xlink:to="loc_us-gaap_DepreciationAndAmortization" use="optional" order="16" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses" xlink:to="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts" use="optional" order="17" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/CondensedConsolidatedStatementsOfOperations">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="loc_us-gaap_NonoperatingIncomeExpense" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:to="loc_us-gaap_NonoperatingIncomeExpense" use="optional" order="18" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xlink:label="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense" xlink:to="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" use="optional" order="19" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense" xlink:to="loc_us-gaap_InterestExpense" use="optional" order="20" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ExtinguishmentOfDebtGainLossNetOfTax" xlink:label="loc_us-gaap_ExtinguishmentOfDebtGainLossNetOfTax" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense" xlink:to="loc_us-gaap_ExtinguishmentOfDebtGainLossNetOfTax" use="optional" order="21" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:to="loc_us-gaap_OperatingIncomeLoss" use="optional" order="22" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaap_GrossProfit" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss" xlink:to="loc_us-gaap_GrossProfit" use="optional" order="23" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization" xlink:label="loc_us-gaap_CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit" xlink:to="loc_us-gaap_CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization" use="optional" order="24" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostOfGoodsAndServicesSoldAmortization" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSoldAmortization" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSoldAmortization" use="optional" order="25" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit" xlink:to="loc_us-gaap_Revenues" use="optional" order="26" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingExpenses" xlink:label="loc_us-gaap_OperatingExpenses" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss" xlink:to="loc_us-gaap_OperatingExpenses" use="optional" order="27" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SellingAndMarketingExpense" xlink:label="loc_us-gaap_SellingAndMarketingExpense" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses" xlink:to="loc_us-gaap_SellingAndMarketingExpense" use="optional" order="28" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense" use="optional" order="29" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense" use="optional" order="30" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DepreciationAndAmortization" xlink:label="loc_us-gaap_DepreciationAndAmortization" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses" xlink:to="loc_us-gaap_DepreciationAndAmortization" use="optional" order="31" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses" xlink:to="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts" use="optional" order="32" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/RevenueScheduleOfRevenueRemainingPerformanceObligationDetail">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligation" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_RevenueRemainingPerformanceObligationCurrent" xlink:label="loc_dh_RevenueRemainingPerformanceObligationCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligation" xlink:to="loc_dh_RevenueRemainingPerformanceObligationCurrent" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_RevenueRemainingPerformanceObligationNoncurrent" xlink:label="loc_dh_RevenueRemainingPerformanceObligationNoncurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligation" xlink:to="loc_dh_RevenueRemainingPerformanceObligationNoncurrent" use="optional" order="2" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/CondensedConsolidatedStatementsOfCashFlows">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:label="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" use="optional" order="2" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" use="optional" order="3" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" use="optional" order="4" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromIssuanceOfUnsecuredDebt" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfUnsecuredDebt" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfUnsecuredDebt" use="optional" order="5" weight="1" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_ProceedsFromDelayedDrawTermLoan" xlink:label="loc_dh_ProceedsFromDelayedDrawTermLoan" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="loc_dh_ProceedsFromDelayedDrawTermLoan" use="optional" order="6" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromLongTermLinesOfCredit" xlink:label="loc_us-gaap_ProceedsFromLongTermLinesOfCredit" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaap_ProceedsFromLongTermLinesOfCredit" use="optional" order="7" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RepaymentsOfUnsecuredDebt" xlink:label="loc_us-gaap_RepaymentsOfUnsecuredDebt" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaap_RepaymentsOfUnsecuredDebt" use="optional" order="8" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RepaymentsOfLongTermLinesOfCredit" xlink:label="loc_us-gaap_RepaymentsOfLongTermLinesOfCredit" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaap_RepaymentsOfLongTermLinesOfCredit" use="optional" order="9" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsOfDebtIssuanceCosts" xlink:label="loc_us-gaap_PaymentsOfDebtIssuanceCosts" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaap_PaymentsOfDebtIssuanceCosts" use="optional" order="10" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsOfCapitalDistribution" xlink:label="loc_us-gaap_PaymentsOfCapitalDistribution" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaap_PaymentsOfCapitalDistribution" use="optional" order="11" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromPartnershipContribution" xlink:label="loc_us-gaap_ProceedsFromPartnershipContribution" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaap_ProceedsFromPartnershipContribution" use="optional" order="12" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentForContingentConsiderationLiabilityFinancingActivities" xlink:label="loc_us-gaap_PaymentForContingentConsiderationLiabilityFinancingActivities" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaap_PaymentForContingentConsiderationLiabilityFinancingActivities" use="optional" order="13" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromIssuanceOrSaleOfEquity" xlink:label="loc_us-gaap_ProceedsFromIssuanceOrSaleOfEquity" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaap_ProceedsFromIssuanceOrSaleOfEquity" use="optional" order="14" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsForRepurchaseOfEquity" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfEquity" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaap_PaymentsForRepurchaseOfEquity" use="optional" order="15" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsOfStockIssuanceCosts" xlink:label="loc_us-gaap_PaymentsOfStockIssuanceCosts" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaap_PaymentsOfStockIssuanceCosts" use="optional" order="16" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" use="optional" order="17" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaap_NetIncomeLoss" use="optional" order="18" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization" use="optional" order="19" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AmortizationOfDeferredCharges" xlink:label="loc_us-gaap_AmortizationOfDeferredCharges" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaap_AmortizationOfDeferredCharges" use="optional" order="20" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaap_ShareBasedCompensation" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaap_ShareBasedCompensation" use="optional" order="21" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaidInKindInterest" xlink:label="loc_us-gaap_PaidInKindInterest" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaap_PaidInKindInterest" use="optional" order="22" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AmortizationOfFinancingCosts" xlink:label="loc_us-gaap_AmortizationOfFinancingCosts" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaap_AmortizationOfFinancingCosts" use="optional" order="23" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationAsset1" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationAsset1" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationAsset1" use="optional" order="24" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProvisionForDoubtfulAccounts" xlink:label="loc_us-gaap_ProvisionForDoubtfulAccounts" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaap_ProvisionForDoubtfulAccounts" use="optional" order="25" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt" use="optional" order="26" weight="-1" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_AmortizationOfDeferredContractCosts" xlink:label="loc_dh_AmortizationOfDeferredContractCosts" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_dh_AmortizationOfDeferredContractCosts" use="optional" order="27" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable" use="optional" order="28" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" use="optional" order="29" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredCharges" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredCharges" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaap_IncreaseDecreaseInDeferredCharges" use="optional" order="30" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" use="optional" order="31" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredRevenue" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredRevenue" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaap_IncreaseDecreaseInDeferredRevenue" use="optional" order="32" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/CondensedConsolidatedStatementsOfCashFlows">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostOfGoodsAndServicesSoldDepreciationAndAmortization" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSoldDepreciationAndAmortization" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_NoncashOrPartNoncashAcquisitionCapitalContribution" xlink:label="loc_dh_NoncashOrPartNoncashAcquisitionCapitalContribution" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CostOfGoodsAndServicesSoldDepreciationAndAmortization" xlink:to="loc_dh_NoncashOrPartNoncashAcquisitionCapitalContribution" use="optional" order="33" weight="-1" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_NoncashOrPartNoncashAcquisitionContingentConsideration" xlink:label="loc_dh_NoncashOrPartNoncashAcquisitionContingentConsideration" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CostOfGoodsAndServicesSoldDepreciationAndAmortization" xlink:to="loc_dh_NoncashOrPartNoncashAcquisitionContingentConsideration" use="optional" order="34" weight="-1" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_NoncashOrPartNoncashAcquisitionConsiderationPaidToFormerMembers" xlink:label="loc_dh_NoncashOrPartNoncashAcquisitionConsiderationPaidToFormerMembers" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CostOfGoodsAndServicesSoldDepreciationAndAmortization" xlink:to="loc_dh_NoncashOrPartNoncashAcquisitionConsiderationPaidToFormerMembers" use="optional" order="35" weight="-1" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_ConsiderationPaidToFormerMembersIncludedInAccruedExpenses" xlink:label="loc_dh_ConsiderationPaidToFormerMembersIncludedInAccruedExpenses" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CostOfGoodsAndServicesSoldDepreciationAndAmortization" xlink:to="loc_dh_ConsiderationPaidToFormerMembersIncludedInAccruedExpenses" use="optional" order="36" weight="-1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/CondensedConsolidatedStatementsOfComprehensiveLoss">
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_ComprehensiveIncomeLossBeforeReorganizationTransactionsAndNoncontrollingInterests" xlink:label="loc_dh_ComprehensiveIncomeLossBeforeReorganizationTransactionsAndNoncontrollingInterests" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_dh_ComprehensiveIncomeLossBeforeReorganizationTransactionsAndNoncontrollingInterests" xlink:to="loc_us-gaap_NetIncomeLoss" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_dh_ComprehensiveIncomeLossBeforeReorganizationTransactionsAndNoncontrollingInterests" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" use="optional" order="2" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/CondensedConsolidatedStatementsOfComprehensiveLoss">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_ComprehensiveIncomeLossBeforeNoncontrollingInterests" xlink:label="loc_dh_ComprehensiveIncomeLossBeforeNoncontrollingInterests" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1" xlink:to="loc_dh_ComprehensiveIncomeLossBeforeNoncontrollingInterests" use="optional" order="3" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest" use="optional" order="4" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/LongTermDebtScheduleOfFuturePrincipalPaymentsDetail">
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_LongTermDebtNet" xlink:label="loc_dh_LongTermDebtNet" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_dh_LongTermDebtNet" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_dh_LongTermDebtNet" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" use="optional" order="2" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_dh_LongTermDebtNet" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" use="optional" order="3" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_dh_LongTermDebtNet" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" use="optional" order="4" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_dh_LongTermDebtNet" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" use="optional" order="5" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_dh_LongTermDebtNet" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" use="optional" order="6" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/IncomeTaxesScheduleOfReconciliationOfIncomeTaxExpenseDetail">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" use="optional" order="2" weight="1" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_EffectiveIncomeTaxRateReconciliationPermanentDifferences" xlink:label="loc_dh_EffectiveIncomeTaxRateReconciliationPermanentDifferences" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="loc_dh_EffectiveIncomeTaxRateReconciliationPermanentDifferences" use="optional" order="3" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseResearchAndDevelopment" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseResearchAndDevelopment" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseResearchAndDevelopment" use="optional" order="4" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" use="optional" order="5" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" use="optional" order="6" weight="1" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_EffectiveIncomeTaxRateReconciliationProvisionToReturnAdjustments" xlink:label="loc_dh_EffectiveIncomeTaxRateReconciliationProvisionToReturnAdjustments" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="loc_dh_EffectiveIncomeTaxRateReconciliationProvisionToReturnAdjustments" use="optional" order="7" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments" use="optional" order="8" weight="1" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_EffectiveIncomeTaxRateReconciliationPassThroughIncomeNotSubjectToTax" xlink:label="loc_dh_EffectiveIncomeTaxRateReconciliationPassThroughIncomeNotSubjectToTax" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="loc_dh_EffectiveIncomeTaxRateReconciliationPassThroughIncomeNotSubjectToTax" use="optional" order="9" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/IncomeTaxesScheduleOfComponentsOfIncomeTaxProvisionOrBenefitDetail">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_CurrentIncomeTaxExpenseBenefit" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeTaxExpenseBenefit" xlink:to="loc_us-gaap_CurrentIncomeTaxExpenseBenefit" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CurrentFederalTaxExpenseBenefit" xlink:label="loc_us-gaap_CurrentFederalTaxExpenseBenefit" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:to="loc_us-gaap_CurrentFederalTaxExpenseBenefit" use="optional" order="2" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CurrentStateAndLocalTaxExpenseBenefit" xlink:label="loc_us-gaap_CurrentStateAndLocalTaxExpenseBenefit" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:to="loc_us-gaap_CurrentStateAndLocalTaxExpenseBenefit" use="optional" order="3" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_DeferredIncomeTaxExpenseBenefit" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeTaxExpenseBenefit" xlink:to="loc_us-gaap_DeferredIncomeTaxExpenseBenefit" use="optional" order="4" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredFederalIncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_DeferredFederalIncomeTaxExpenseBenefit" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:to="loc_us-gaap_DeferredFederalIncomeTaxExpenseBenefit" use="optional" order="5" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:to="loc_us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit" use="optional" order="6" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/GoodwillAndIntangibleAssetsScheduleOfCarryingAmountsOfGoodwillAndIntangibleAssetsDetail">
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_TotalGoodwillAndIntangibleAssetsNet" xlink:label="loc_dh_TotalGoodwillAndIntangibleAssetsNet" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_dh_TotalGoodwillAndIntangibleAssetsNet" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" use="optional" order="1" weight="-1" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_IntangibleAssetsGrossIncludingGoodwill" xlink:label="loc_dh_IntangibleAssetsGrossIncludingGoodwill" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_dh_TotalGoodwillAndIntangibleAssetsNet" xlink:to="loc_dh_IntangibleAssetsGrossIncludingGoodwill" use="optional" order="2" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/AccruedExpensesAndOtherCurrentLiabilitiesScheduleOfAccruedExpensesAndOtherCurrentLiabilitiesDetail">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent" xlink:to="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestPayableCurrent" xlink:label="loc_us-gaap_InterestPayableCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent" xlink:to="loc_us-gaap_InterestPayableCurrent" use="optional" order="2" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationLiabilityCurrent" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityCurrent" use="optional" order="3" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SalesAndExciseTaxPayableCurrent" xlink:label="loc_us-gaap_SalesAndExciseTaxPayableCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent" xlink:to="loc_us-gaap_SalesAndExciseTaxPayableCurrent" use="optional" order="4" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredRentCreditCurrent" xlink:label="loc_us-gaap_DeferredRentCreditCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent" xlink:to="loc_us-gaap_DeferredRentCreditCurrent" use="optional" order="5" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_OtherAccruedLiabilitiesCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent" xlink:to="loc_us-gaap_OtherAccruedLiabilitiesCurrent" use="optional" order="6" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/CommitmentsAndContingenciesScheduleOfMinimumFutureRentalPaymentsDetail">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsRemainderOfFiscalYear" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsRemainderOfFiscalYear" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsRemainderOfFiscalYear" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" use="optional" order="2" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" use="optional" order="3" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" use="optional" order="4" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" use="optional" order="5" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter" use="optional" order="6" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/BusinessCombinationsScheduleOfReconciliationOfPurchasePriceToTheCapitalContributionDetail">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CapitalUnitsNetAmount" xlink:label="loc_us-gaap_CapitalUnitsNetAmount" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CapitalUnitsNetAmount" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" use="optional" order="1" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionCostOfAcquiredEntityTransactionCosts" xlink:label="loc_us-gaap_BusinessAcquisitionCostOfAcquiredEntityTransactionCosts" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CapitalUnitsNetAmount" xlink:to="loc_us-gaap_BusinessAcquisitionCostOfAcquiredEntityTransactionCosts" use="optional" order="2" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCredit" xlink:label="loc_us-gaap_LineOfCredit" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CapitalUnitsNetAmount" xlink:to="loc_us-gaap_LineOfCredit" use="optional" order="3" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/IncomeTaxesScheduleOfComponentsOfDeferredTaxAssetsAndLiabilitiesDetail">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsNet" xlink:label="loc_us-gaap_DeferredTaxAssetsNet" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsGross" xlink:label="loc_us-gaap_DeferredTaxAssetsGross" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_DeferredTaxAssetsNet" xlink:to="loc_us-gaap_DeferredTaxAssetsGross" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwards" xlink:label="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwards" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_DeferredTaxAssetsGross" xlink:to="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwards" use="optional" order="2" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities" xlink:label="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_DeferredTaxAssetsGross" xlink:to="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities" use="optional" order="3" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsUnrealizedCurrencyLosses" xlink:label="loc_us-gaap_DeferredTaxAssetsUnrealizedCurrencyLosses" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_DeferredTaxAssetsGross" xlink:to="loc_us-gaap_DeferredTaxAssetsUnrealizedCurrencyLosses" use="optional" order="4" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsValuationAllowance" xlink:label="loc_us-gaap_DeferredTaxAssetsValuationAllowance" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_DeferredTaxAssetsNet" xlink:to="loc_us-gaap_DeferredTaxAssetsValuationAllowance" use="optional" order="5" weight="-1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/BusinessCombinationsScheduleOfRecognizedAssetsAndLibailitiesPertainingToBusinessCombinationDetail">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables" use="optional" order="2" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets" use="optional" order="3" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" use="optional" order="4" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill" use="optional" order="5" weight="1" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayables" xlink:label="loc_dh_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayables" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:to="loc_dh_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayables" use="optional" order="6" weight="-1" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesDeferredRevenues" xlink:label="loc_dh_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesDeferredRevenues" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:to="loc_dh_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesDeferredRevenues" use="optional" order="7" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" use="optional" order="8" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:to="loc_us-gaap_Goodwill" use="optional" order="9" weight="1" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredContractCosts" xlink:label="loc_dh_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredContractCosts" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:to="loc_dh_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredContractCosts" use="optional" order="10" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets" use="optional" order="11" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" use="optional" order="12" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/LongTermDebtScheduleOfLongTermDebtInstrumentsDetail">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="loc_us-gaap_LongTermDebtNoncurrent" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LongTermDebtNoncurrent" xlink:to="loc_us-gaap_LongTermDebt" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LongTermDebt" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount" use="optional" order="2" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LongTermDebt" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" use="optional" order="3" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:label="loc_us-gaap_LongTermDebtCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LongTermDebtNoncurrent" xlink:to="loc_us-gaap_LongTermDebtCurrent" use="optional" order="4" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/CommitmentsAndContingenciesScheduleOfEstimatedAnnualMinimumPurchaseCommitmentsDetail">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PurchaseObligation" xlink:label="loc_us-gaap_PurchaseObligation" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PurchaseObligationFutureMinimumPaymentsRemainderOfFiscalYear" xlink:label="loc_us-gaap_PurchaseObligationFutureMinimumPaymentsRemainderOfFiscalYear" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_PurchaseObligation" xlink:to="loc_us-gaap_PurchaseObligationFutureMinimumPaymentsRemainderOfFiscalYear" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PurchaseObligationDueInNextTwelveMonths" xlink:label="loc_us-gaap_PurchaseObligationDueInNextTwelveMonths" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_PurchaseObligation" xlink:to="loc_us-gaap_PurchaseObligationDueInNextTwelveMonths" use="optional" order="2" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PurchaseObligationDueInSecondYear" xlink:label="loc_us-gaap_PurchaseObligationDueInSecondYear" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_PurchaseObligation" xlink:to="loc_us-gaap_PurchaseObligationDueInSecondYear" use="optional" order="3" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PurchaseObligationDueInThirdYear" xlink:label="loc_us-gaap_PurchaseObligationDueInThirdYear" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_PurchaseObligation" xlink:to="loc_us-gaap_PurchaseObligationDueInThirdYear" use="optional" order="4" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PurchaseObligationDueInFourthYear" xlink:label="loc_us-gaap_PurchaseObligationDueInFourthYear" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_PurchaseObligation" xlink:to="loc_us-gaap_PurchaseObligationDueInFourthYear" use="optional" order="5" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PurchaseObligationDueAfterFifthYear" xlink:label="loc_us-gaap_PurchaseObligationDueAfterFifthYear" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_PurchaseObligation" xlink:to="loc_us-gaap_PurchaseObligationDueAfterFifthYear" use="optional" order="6" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/LossPerShareScheduleOfReconciliationOfEarningsPerShareBasicAndDilutedDetail">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss" xlink:to="loc_us-gaap_ProfitLoss" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_NetLossAttributableToDefinitiveOpcoBeforeReorganizationTransactions" xlink:label="loc_dh_NetLossAttributableToDefinitiveOpcoBeforeReorganizationTransactions" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss" xlink:to="loc_dh_NetLossAttributableToDefinitiveOpcoBeforeReorganizationTransactions" use="optional" order="2" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" use="optional" order="3" weight="-1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/CondensedConsolidatedBalanceSheets">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets" xlink:to="loc_us-gaap_AssetsCurrent" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue" use="optional" order="2" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent" use="optional" order="3" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent" use="optional" order="4" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerAssetNetCurrent" xlink:label="loc_us-gaap_ContractWithCustomerAssetNetCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent" xlink:to="loc_us-gaap_ContractWithCustomerAssetNetCurrent" use="optional" order="5" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet" use="optional" order="6" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="loc_us-gaap_OtherAssetsNoncurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets" xlink:to="loc_us-gaap_OtherAssetsNoncurrent" use="optional" order="7" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerAssetNetNoncurrent" xlink:label="loc_us-gaap_ContractWithCustomerAssetNetNoncurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets" xlink:to="loc_us-gaap_ContractWithCustomerAssetNetNoncurrent" use="optional" order="8" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxAssetsNet" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets" xlink:to="loc_us-gaap_DeferredIncomeTaxAssetsNet" use="optional" order="9" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill" use="optional" order="10" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets" xlink:to="loc_us-gaap_Goodwill" use="optional" order="11" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/CondensedConsolidatedBalanceSheets">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaap_AccountsPayableCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent" xlink:to="loc_us-gaap_AccountsPayableCurrent" use="optional" order="12" weight="1" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_AccruedExpensesAndOtherCurrentLiabilities" xlink:label="loc_dh_AccruedExpensesAndOtherCurrentLiabilities" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent" xlink:to="loc_dh_AccruedExpensesAndOtherCurrentLiabilities" use="optional" order="13" weight="1" />
<loc xlink:type="locator" xlink:href="dh-20210930.xsd#dh_MembersDistributionPayable" xlink:label="loc_dh_MembersDistributionPayable" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent" xlink:to="loc_dh_MembersDistributionPayable" use="optional" order="14" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredRevenueCurrent" xlink:label="loc_us-gaap_DeferredRevenueCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent" xlink:to="loc_us-gaap_DeferredRevenueCurrent" use="optional" order="15" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtCurrent" xlink:label="loc_us-gaap_DebtCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent" xlink:to="loc_us-gaap_DebtCurrent" use="optional" order="16" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.definitivehc.com/role/CondensedConsolidatedBalanceSheets">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="loc_us-gaap_Liabilities" use="optional" order="17" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredRevenueNoncurrent" xlink:label="loc_us-gaap_DeferredRevenueNoncurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities" xlink:to="loc_us-gaap_DeferredRevenueNoncurrent" use="optional" order="18" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="loc_us-gaap_LongTermDebtNoncurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities" xlink:to="loc_us-gaap_LongTermDebtNoncurrent" use="optional" order="19" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent" use="optional" order="20" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilityForUncertainTaxPositionsNoncurrent" xlink:label="loc_us-gaap_LiabilityForUncertainTaxPositionsNoncurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities" xlink:to="loc_us-gaap_LiabilityForUncertainTaxPositionsNoncurrent" use="optional" order="21" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet" use="optional" order="22" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" use="optional" order="23" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit" use="optional" order="24" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" use="optional" order="25" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockValue" xlink:label="loc_us-gaap_CommonStockValue" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:to="loc_us-gaap_CommonStockValue" use="optional" order="26" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="loc_us-gaap_AdditionalPaidInCapital" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:to="loc_us-gaap_AdditionalPaidInCapital" use="optional" order="27" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MinorityInterest" xlink:label="loc_us-gaap_MinorityInterest" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:to="loc_us-gaap_MinorityInterest" use="optional" order="28" weight="1" />
</calculationLink>
</linkbase>
