<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2022 Workiva-->
<!--r:29a4b4dc-8cca-4a2c-8b00-1653a7b25685,g:4140688d-8727-4745-9ca5-400c87633167-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:roleRef roleURI="http://www.nektar.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETS" xlink:type="simple" xlink:href="nktr-20220630.xsd#CONDENSEDCONSOLIDATEDBALANCESHEETS"/>
  <link:calculationLink xlink:role="http://www.nektar.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETS" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_18836d77-2500-4c55-a28e-0b9a0cd93501" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsCurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_ca5d0520-8445-4f69-b205-deb0fb3d4d05" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_18836d77-2500-4c55-a28e-0b9a0cd93501" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_ca5d0520-8445-4f69-b205-deb0fb3d4d05" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent_b9944adb-8978-46b3-9964-758626fb41c1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_18836d77-2500-4c55-a28e-0b9a0cd93501" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent_b9944adb-8978-46b3-9964-758626fb41c1" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_89b0be14-0dcd-4079-a0bd-36716af8b054" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_18836d77-2500-4c55-a28e-0b9a0cd93501" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_89b0be14-0dcd-4079-a0bd-36716af8b054" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNet_f826b810-d3fb-48da-ad0f-485d2890116a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InventoryNet"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_18836d77-2500-4c55-a28e-0b9a0cd93501" xlink:to="loc_us-gaap_InventoryNet_f826b810-d3fb-48da-ad0f-485d2890116a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsCurrent_2e648a19-0b5b-4680-ac1d-afb280c8bb7b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherAssetsCurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_18836d77-2500-4c55-a28e-0b9a0cd93501" xlink:to="loc_us-gaap_OtherAssetsCurrent_2e648a19-0b5b-4680-ac1d-afb280c8bb7b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_ca66f533-7a7f-415b-94b1-eadae268a4c2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockValue_9b10d3d2-38dc-4f8b-98a5-6033de7ba442" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PreferredStockValue"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_ca66f533-7a7f-415b-94b1-eadae268a4c2" xlink:to="loc_us-gaap_PreferredStockValue_9b10d3d2-38dc-4f8b-98a5-6033de7ba442" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_068f6562-1823-4a0d-addc-a08f46fb91c8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockValue"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_ca66f533-7a7f-415b-94b1-eadae268a4c2" xlink:to="loc_us-gaap_CommonStockValue_068f6562-1823-4a0d-addc-a08f46fb91c8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalCommonStock_f0059c22-5e45-4035-a1c5-e2593d29f501" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdditionalPaidInCapitalCommonStock"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_ca66f533-7a7f-415b-94b1-eadae268a4c2" xlink:to="loc_us-gaap_AdditionalPaidInCapitalCommonStock_f0059c22-5e45-4035-a1c5-e2593d29f501" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_56bf7b98-e5d0-4ef5-badd-1cedc9b38e82" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_ca66f533-7a7f-415b-94b1-eadae268a4c2" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_56bf7b98-e5d0-4ef5-badd-1cedc9b38e82" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_351d9d2a-396d-413c-af54-f9cadc22a138" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_ca66f533-7a7f-415b-94b1-eadae268a4c2" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_351d9d2a-396d-413c-af54-f9cadc22a138" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_d2683349-23ff-4e50-a895-ee762b0be0b6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Liabilities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_33eb55d4-667d-4f93-a204-8550db762d2e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_d2683349-23ff-4e50-a895-ee762b0be0b6" xlink:to="loc_us-gaap_LiabilitiesCurrent_33eb55d4-667d-4f93-a204-8550db762d2e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_ce03c7c3-ff73-4374-9685-c6e7c301ef21" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_d2683349-23ff-4e50-a895-ee762b0be0b6" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_ce03c7c3-ff73-4374-9685-c6e7c301ef21" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesNonCurrentNetOfIssuanceCosts_290868c6-b365-48b5-9669-f747bf16e0fa" xlink:href="nktr-20220630.xsd#nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesNonCurrentNetOfIssuanceCosts"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_d2683349-23ff-4e50-a895-ee762b0be0b6" xlink:to="loc_nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesNonCurrentNetOfIssuanceCosts_290868c6-b365-48b5-9669-f747bf16e0fa" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_04e90bb7-e8ca-4222-804e-aa7195277d47" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_d2683349-23ff-4e50-a895-ee762b0be0b6" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_04e90bb7-e8ca-4222-804e-aa7195277d47" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilitiesNoncurrent_fb1179ce-5630-4644-94b0-97749fe7c2a6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeLiabilitiesNoncurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_d2683349-23ff-4e50-a895-ee762b0be0b6" xlink:to="loc_us-gaap_DerivativeLiabilitiesNoncurrent_fb1179ce-5630-4644-94b0-97749fe7c2a6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_680e9500-b633-4ceb-98dd-04864c9ed514" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_a49b1722-f7d8-4567-bc25-26ef49973b3b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Liabilities"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_680e9500-b633-4ceb-98dd-04864c9ed514" xlink:to="loc_us-gaap_Liabilities_a49b1722-f7d8-4567-bc25-26ef49973b3b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_7cbb2240-79ea-49e3-bc17-e6f7a4c245b1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_680e9500-b633-4ceb-98dd-04864c9ed514" xlink:to="loc_us-gaap_CommitmentsAndContingencies_7cbb2240-79ea-49e3-bc17-e6f7a4c245b1" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_59da2c69-b661-4f6a-bcf8-519278379e1b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_680e9500-b633-4ceb-98dd-04864c9ed514" xlink:to="loc_us-gaap_StockholdersEquity_59da2c69-b661-4f6a-bcf8-519278379e1b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_26b4e6fc-5525-48af-93c9-82e6165229f6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Assets"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_0784b571-249f-40a0-a1a4-10bff5bccd66" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_26b4e6fc-5525-48af-93c9-82e6165229f6" xlink:to="loc_us-gaap_AssetsCurrent_0784b571-249f-40a0-a1a4-10bff5bccd66" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecuritiesNoncurrent_6ac425fc-aa1b-41e4-a9fb-aa8f17fdecb2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecuritiesNoncurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_26b4e6fc-5525-48af-93c9-82e6165229f6" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecuritiesNoncurrent_6ac425fc-aa1b-41e4-a9fb-aa8f17fdecb2" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_0b61ac63-6d6b-41b7-a1f8-2a7a27682644" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_26b4e6fc-5525-48af-93c9-82e6165229f6" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_0b61ac63-6d6b-41b7-a1f8-2a7a27682644" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_61306046-8afd-4816-aa80-bb8f4470a6ca" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_26b4e6fc-5525-48af-93c9-82e6165229f6" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_61306046-8afd-4816-aa80-bb8f4470a6ca" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_4a7f70f2-7210-4872-88a4-24cacfd85f7d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_26b4e6fc-5525-48af-93c9-82e6165229f6" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_4a7f70f2-7210-4872-88a4-24cacfd85f7d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_d1e793ca-d71c-44d5-ac22-2cc4e97e77f3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Goodwill"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_26b4e6fc-5525-48af-93c9-82e6165229f6" xlink:to="loc_us-gaap_Goodwill_d1e793ca-d71c-44d5-ac22-2cc4e97e77f3" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_d7f2ce18-e731-4215-bf0d-37840a631863" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_0b3cbeeb-6323-4b42-bdd4-6d4fb209e904" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_d7f2ce18-e731-4215-bf0d-37840a631863" xlink:to="loc_us-gaap_AccountsPayableCurrent_0b3cbeeb-6323-4b42-bdd4-6d4fb209e904" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_c4f5b61d-50be-4cf0-8321-bf23b2975c00" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_d7f2ce18-e731-4215-bf0d-37840a631863" xlink:to="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_c4f5b61d-50be-4cf0-8321-bf23b2975c00" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nktr_AccruedClinicalTrialExpensesCurrent_4899ed7d-72b2-429e-92e9-3c9a2328413d" xlink:href="nktr-20220630.xsd#nktr_AccruedClinicalTrialExpensesCurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_d7f2ce18-e731-4215-bf0d-37840a631863" xlink:to="loc_nktr_AccruedClinicalTrialExpensesCurrent_4899ed7d-72b2-429e-92e9-3c9a2328413d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAccruedLiabilitiesCurrent_1b9e558f-919c-4cb8-b848-55b9ad7e3444" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherAccruedLiabilitiesCurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_d7f2ce18-e731-4215-bf0d-37840a631863" xlink:to="loc_us-gaap_OtherAccruedLiabilitiesCurrent_1b9e558f-919c-4cb8-b848-55b9ad7e3444" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent_a87d9d16-ee8b-47e8-b920-b73342ded470" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLiabilityCurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_d7f2ce18-e731-4215-bf0d-37840a631863" xlink:to="loc_us-gaap_OperatingLeaseLiabilityCurrent_a87d9d16-ee8b-47e8-b920-b73342ded470" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.nektar.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONS" xlink:type="simple" xlink:href="nktr-20220630.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONS"/>
  <link:calculationLink xlink:role="http://www.nektar.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONS" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_c3297f63-b210-4601-80ea-66ce22c8a7f2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_83d28300-b0c0-4b9d-af8c-952a8affe2bf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_c3297f63-b210-4601-80ea-66ce22c8a7f2" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_83d28300-b0c0-4b9d-af8c-952a8affe2bf" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_0bb8c178-e72a-4eb3-8b6e-78b0cf315125" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_c3297f63-b210-4601-80ea-66ce22c8a7f2" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_0bb8c178-e72a-4eb3-8b6e-78b0cf315125" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_f073c6dd-4cd8-4554-a976-af8e02caf720" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_954aa453-0734-472a-bc06-39f6000cafa8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_f073c6dd-4cd8-4554-a976-af8e02caf720" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_954aa453-0734-472a-bc06-39f6000cafa8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpenses_6f601729-2f4a-4f7a-a8de-61af5ebb5bb2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CostsAndExpenses"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_f073c6dd-4cd8-4554-a976-af8e02caf720" xlink:to="loc_us-gaap_CostsAndExpenses_6f601729-2f4a-4f7a-a8de-61af5ebb5bb2" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_7eeadbf0-7e96-46ae-91e6-357fa466ac97" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:loc xlink:type="locator" xlink:label="loc_nktr_NonCashInterestExpenseRelatedToSaleOfRoyalties_0508ffa7-757d-4655-a967-b1284abf5b01" xlink:href="nktr-20220630.xsd#nktr_NonCashInterestExpenseRelatedToSaleOfRoyalties"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_7eeadbf0-7e96-46ae-91e6-357fa466ac97" xlink:to="loc_nktr_NonCashInterestExpenseRelatedToSaleOfRoyalties_0508ffa7-757d-4655-a967-b1284abf5b01" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_83d05890-8352-444b-a39e-a45ad4068dd8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_7eeadbf0-7e96-46ae-91e6-357fa466ac97" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_83d05890-8352-444b-a39e-a45ad4068dd8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueAdjustment_0448ee3d-da95-4fdf-8447-4e455acfa32c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesFairValueAdjustment"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_7eeadbf0-7e96-46ae-91e6-357fa466ac97" xlink:to="loc_us-gaap_LiabilitiesFairValueAdjustment_0448ee3d-da95-4fdf-8447-4e455acfa32c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_229eb482-7395-4f16-a975-57b899e6f3fa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_144d9c3f-2061-4a10-a53a-645819282aa6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_229eb482-7395-4f16-a975-57b899e6f3fa" xlink:to="loc_us-gaap_OperatingIncomeLoss_144d9c3f-2061-4a10-a53a-645819282aa6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_455eb113-3127-4827-b821-ac9e69f2cf13" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_229eb482-7395-4f16-a975-57b899e6f3fa" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_455eb113-3127-4827-b821-ac9e69f2cf13" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpenses_4c6476c6-5954-4e0d-a3c1-24e9e9338e74" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CostsAndExpenses"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_436f7773-72d1-4d9d-8f8f-397b2cfe1d5c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CostsAndExpenses_4c6476c6-5954-4e0d-a3c1-24e9e9338e74" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_436f7773-72d1-4d9d-8f8f-397b2cfe1d5c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_20311dc2-2f6f-4214-8749-90f4c91fbb81" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CostsAndExpenses_4c6476c6-5954-4e0d-a3c1-24e9e9338e74" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_20311dc2-2f6f-4214-8749-90f4c91fbb81" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_94884137-0c60-4b6e-8268-07c768b01a1e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CostsAndExpenses_4c6476c6-5954-4e0d-a3c1-24e9e9338e74" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_94884137-0c60-4b6e-8268-07c768b01a1e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_f5b4b855-df76-4d8f-9971-ff36a3c2c945" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RestructuringCharges"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CostsAndExpenses_4c6476c6-5954-4e0d-a3c1-24e9e9338e74" xlink:to="loc_us-gaap_RestructuringCharges_f5b4b855-df76-4d8f-9971-ff36a3c2c945" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.nektar.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVELOSS" xlink:type="simple" xlink:href="nktr-20220630.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVELOSS"/>
  <link:calculationLink xlink:role="http://www.nektar.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVELOSS" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_1c744eff-07f1-47df-8baa-316961c9bbb0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_a8fc1642-e2e2-4538-9302-fecd26835b01" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax_1c744eff-07f1-47df-8baa-316961c9bbb0" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_a8fc1642-e2e2-4538-9302-fecd26835b01" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_814153c0-0fff-4a91-bbdb-62fea5030531" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax_1c744eff-07f1-47df-8baa-316961c9bbb0" xlink:to="loc_us-gaap_NetIncomeLoss_814153c0-0fff-4a91-bbdb-62fea5030531" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_aae574d4-4d19-4ec8-a8af-df77d6d6a3c2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_ce29a6e2-3432-4a03-93a1-24ca8b05c1ef" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_aae574d4-4d19-4ec8-a8af-df77d6d6a3c2" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_ce29a6e2-3432-4a03-93a1-24ca8b05c1ef" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_e00561a8-2900-4163-aec3-3f50914cc873" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_aae574d4-4d19-4ec8-a8af-df77d6d6a3c2" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_e00561a8-2900-4163-aec3-3f50914cc873" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.nektar.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWS" xlink:type="simple" xlink:href="nktr-20220630.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWS"/>
  <link:calculationLink xlink:role="http://www.nektar.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWS" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_310a4b58-324e-480c-81c6-bad5d00cd98c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlans_708b5d13-6331-42d1-a308-7ac702266a01" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlans"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_310a4b58-324e-480c-81c6-bad5d00cd98c" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlans_708b5d13-6331-42d1-a308-7ac702266a01" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromDerivativeInstrumentFinancingActivities_56ce95d3-c2b7-4fa9-a099-85a6fdf16ca9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProceedsFromDerivativeInstrumentFinancingActivities"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_310a4b58-324e-480c-81c6-bad5d00cd98c" xlink:to="loc_us-gaap_ProceedsFromDerivativeInstrumentFinancingActivities_56ce95d3-c2b7-4fa9-a099-85a6fdf16ca9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_bccecbe7-0794-4b2a-8695-c11538e3b193" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_nktr_IncreaseDecreaseInOperatingLeaseRightOfUseAssetsNetOfOperatingLeaseLiabilities_d8473379-eb1f-42a0-b12a-b8a9818dd797" xlink:href="nktr-20220630.xsd#nktr_IncreaseDecreaseInOperatingLeaseRightOfUseAssetsNetOfOperatingLeaseLiabilities"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_bccecbe7-0794-4b2a-8695-c11538e3b193" xlink:to="loc_nktr_IncreaseDecreaseInOperatingLeaseRightOfUseAssetsNetOfOperatingLeaseLiabilities_d8473379-eb1f-42a0-b12a-b8a9818dd797" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetImpairmentCharges_ede64cc5-75eb-4b81-b169-4812c7142b76" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetImpairmentCharges"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_bccecbe7-0794-4b2a-8695-c11538e3b193" xlink:to="loc_us-gaap_AssetImpairmentCharges_ede64cc5-75eb-4b81-b169-4812c7142b76" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nktr_NonCashRoyaltyRevenueRelatedToSaleOfFutureRoyalties_13a394bf-ecbd-4aff-adbf-1f3d06a5e862" xlink:href="nktr-20220630.xsd#nktr_NonCashRoyaltyRevenueRelatedToSaleOfFutureRoyalties"/>
    <link:calculationArc order="3" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_bccecbe7-0794-4b2a-8695-c11538e3b193" xlink:to="loc_nktr_NonCashRoyaltyRevenueRelatedToSaleOfFutureRoyalties_13a394bf-ecbd-4aff-adbf-1f3d06a5e862" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nktr_NonCashInterestExpenseRelatedToSaleOfRoyalties_b7d89abe-8677-40f4-be96-8b31e2b33d68" xlink:href="nktr-20220630.xsd#nktr_NonCashInterestExpenseRelatedToSaleOfRoyalties"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_bccecbe7-0794-4b2a-8695-c11538e3b193" xlink:to="loc_nktr_NonCashInterestExpenseRelatedToSaleOfRoyalties_b7d89abe-8677-40f4-be96-8b31e2b33d68" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets_96997975-1a07-49a1-af6a-2e7b791e28c6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssets"/>
    <link:calculationArc order="5" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_bccecbe7-0794-4b2a-8695-c11538e3b193" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets_96997975-1a07-49a1-af6a-2e7b791e28c6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationAndAmortization_6b81432f-fa91-4fbc-a115-af2c77197676" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DepreciationAndAmortization"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_bccecbe7-0794-4b2a-8695-c11538e3b193" xlink:to="loc_us-gaap_DepreciationAndAmortization_6b81432f-fa91-4fbc-a115-af2c77197676" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_57b4c309-7e09-4186-8561-2400cb807e72" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities"/>
    <link:calculationArc order="7" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_bccecbe7-0794-4b2a-8695-c11538e3b193" xlink:to="loc_us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_57b4c309-7e09-4186-8561-2400cb807e72" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_c12500bb-c6a9-4969-83b9-b442e00e584c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable"/>
    <link:calculationArc order="8" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_bccecbe7-0794-4b2a-8695-c11538e3b193" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_c12500bb-c6a9-4969-83b9-b442e00e584c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_69731ed9-2b05-42bd-93c8-f7a1aa9e4954" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProfitLoss"/>
    <link:calculationArc order="9" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_bccecbe7-0794-4b2a-8695-c11538e3b193" xlink:to="loc_us-gaap_ProfitLoss_69731ed9-2b05-42bd-93c8-f7a1aa9e4954" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_0aa6b9ef-9609-4dd9-a005-3ecbbbac68c0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:calculationArc order="10" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_bccecbe7-0794-4b2a-8695-c11538e3b193" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_0aa6b9ef-9609-4dd9-a005-3ecbbbac68c0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayable_641ed0ad-3c3d-49bd-a4ce-71a5f9d1ab56" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInAccountsPayable"/>
    <link:calculationArc order="11" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_bccecbe7-0794-4b2a-8695-c11538e3b193" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayable_641ed0ad-3c3d-49bd-a4ce-71a5f9d1ab56" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueAdjustment_d610f911-75fe-4065-a28c-daccaa76f42f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesFairValueAdjustment"/>
    <link:calculationArc order="12" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_bccecbe7-0794-4b2a-8695-c11538e3b193" xlink:to="loc_us-gaap_LiabilitiesFairValueAdjustment_d610f911-75fe-4065-a28c-daccaa76f42f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherAccruedLiabilities_20c32186-0adb-426d-b6ae-4157bea7e327" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInOtherAccruedLiabilities"/>
    <link:calculationArc order="13" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_bccecbe7-0794-4b2a-8695-c11538e3b193" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherAccruedLiabilities_20c32186-0adb-426d-b6ae-4157bea7e327" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentInProcess_9881162f-62a6-4feb-b56f-c1dadb41cd6b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ResearchAndDevelopmentInProcess"/>
    <link:calculationArc order="14" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_bccecbe7-0794-4b2a-8695-c11538e3b193" xlink:to="loc_us-gaap_ResearchAndDevelopmentInProcess_9881162f-62a6-4feb-b56f-c1dadb41cd6b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories_29bf4081-e3ce-4fc6-b092-15a164a76bc3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInInventories"/>
    <link:calculationArc order="15" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_bccecbe7-0794-4b2a-8695-c11538e3b193" xlink:to="loc_us-gaap_IncreaseDecreaseInInventories_29bf4081-e3ce-4fc6-b092-15a164a76bc3" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncashIncomeExpense_d05e8057-2675-4b2b-acbe-6fd106d8ce97" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherNoncashIncomeExpense"/>
    <link:calculationArc order="16" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_bccecbe7-0794-4b2a-8695-c11538e3b193" xlink:to="loc_us-gaap_OtherNoncashIncomeExpense_d05e8057-2675-4b2b-acbe-6fd106d8ce97" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_cce0a987-07ef-4394-b7dc-9d0395db11f2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_956abac3-c777-495b-986e-1e489e13a818" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_cce0a987-07ef-4394-b7dc-9d0395db11f2" xlink:to="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_956abac3-c777-495b-986e-1e489e13a818" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_9c4e94c0-9434-4ed7-8d8c-2978f7a9da1d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_cce0a987-07ef-4394-b7dc-9d0395db11f2" xlink:to="loc_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_9c4e94c0-9434-4ed7-8d8c-2978f7a9da1d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_17878368-020e-4894-a9df-3e5e143c6b27" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <link:calculationArc order="3" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_cce0a987-07ef-4394-b7dc-9d0395db11f2" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_17878368-020e-4894-a9df-3e5e143c6b27" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt_f6f445c3-2b2c-4341-a7a3-387a06cee46b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_cce0a987-07ef-4394-b7dc-9d0395db11f2" xlink:to="loc_us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt_f6f445c3-2b2c-4341-a7a3-387a06cee46b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_a019aeb4-bac9-4e5c-99ed-3cdd7b7b4f42" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_afd4b19b-2250-4388-99a5-baf67f3d7f93" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_a019aeb4-bac9-4e5c-99ed-3cdd7b7b4f42" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_afd4b19b-2250-4388-99a5-baf67f3d7f93" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_18745ffa-325a-4fe5-8bb7-5dcf5ec07970" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_a019aeb4-bac9-4e5c-99ed-3cdd7b7b4f42" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_18745ffa-325a-4fe5-8bb7-5dcf5ec07970" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_47ca39a4-1364-4db2-92d7-6a78b6183a92" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_a019aeb4-bac9-4e5c-99ed-3cdd7b7b4f42" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_47ca39a4-1364-4db2-92d7-6a78b6183a92" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_37efbd95-849e-469f-a6e0-61190e37f3b3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_a019aeb4-bac9-4e5c-99ed-3cdd7b7b4f42" xlink:to="loc_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_37efbd95-849e-469f-a6e0-61190e37f3b3" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.nektar.com/role/CashandInvestmentsinMarketableSecuritiesCashandInvestmentsinMarketableSecuritiesIncludingCashEquivalentsDetail" xlink:type="simple" xlink:href="nktr-20220630.xsd#CashandInvestmentsinMarketableSecuritiesCashandInvestmentsinMarketableSecuritiesIncludingCashEquivalentsDetail"/>
  <link:calculationLink xlink:role="http://www.nektar.com/role/CashandInvestmentsinMarketableSecuritiesCashandInvestmentsinMarketableSecuritiesIncludingCashEquivalentsDetail" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_nktr_CashRestrictedCashCashEquivalentsAndAvailableForSaleInvestments_c940d64f-d5c6-4150-ae7e-67eefac41585" xlink:href="nktr-20220630.xsd#nktr_CashRestrictedCashCashEquivalentsAndAvailableForSaleInvestments"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_f1ad3fa6-7051-4433-a32f-1c63bc6c0da0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_nktr_CashRestrictedCashCashEquivalentsAndAvailableForSaleInvestments_c940d64f-d5c6-4150-ae7e-67eefac41585" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_f1ad3fa6-7051-4433-a32f-1c63bc6c0da0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent_b6141d57-50b7-459b-85c1-d41bfeff3e64" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_nktr_CashRestrictedCashCashEquivalentsAndAvailableForSaleInvestments_c940d64f-d5c6-4150-ae7e-67eefac41585" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent_b6141d57-50b7-459b-85c1-d41bfeff3e64" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecuritiesNoncurrent_584acdf9-4895-4fd8-9615-ba8b228faafb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecuritiesNoncurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_nktr_CashRestrictedCashCashEquivalentsAndAvailableForSaleInvestments_c940d64f-d5c6-4150-ae7e-67eefac41585" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecuritiesNoncurrent_584acdf9-4895-4fd8-9615-ba8b228faafb" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.nektar.com/role/CashandInvestmentsinMarketableSecuritiesPortfolioofCashandInvestmentsinMarketableSecuritiesDetail" xlink:type="simple" xlink:href="nktr-20220630.xsd#CashandInvestmentsinMarketableSecuritiesPortfolioofCashandInvestmentsinMarketableSecuritiesDetail"/>
  <link:calculationLink xlink:role="http://www.nektar.com/role/CashandInvestmentsinMarketableSecuritiesPortfolioofCashandInvestmentsinMarketableSecuritiesDetail" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_8f2ef06d-8b33-4cce-bbc5-c48739911a61" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_c5427238-f7fb-4ebe-8ddb-b1ab141ceef1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_8f2ef06d-8b33-4cce-bbc5-c48739911a61" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_c5427238-f7fb-4ebe-8ddb-b1ab141ceef1" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_26e570aa-d84d-4d2e-adde-48577f9160cb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_8f2ef06d-8b33-4cce-bbc5-c48739911a61" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_26e570aa-d84d-4d2e-adde-48577f9160cb" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_e910351e-4795-4715-97b6-d9921fa43928" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax"/>
    <link:calculationArc order="3" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_8f2ef06d-8b33-4cce-bbc5-c48739911a61" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_e910351e-4795-4715-97b6-d9921fa43928" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nktr_CashRestrictedCashCashEquivalentsAndAvailableForSaleInvestments_895538ce-b85d-48e1-a891-9cef8376f3cf" xlink:href="nktr-20220630.xsd#nktr_CashRestrictedCashCashEquivalentsAndAvailableForSaleInvestments"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_2097b1e9-8f6a-467e-8ed0-fdba29300e0b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_nktr_CashRestrictedCashCashEquivalentsAndAvailableForSaleInvestments_895538ce-b85d-48e1-a891-9cef8376f3cf" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_2097b1e9-8f6a-467e-8ed0-fdba29300e0b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsFairValueDisclosure_0e3447dc-b083-4c97-b429-cfa570d0ee3c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentsFairValueDisclosure"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_nktr_CashRestrictedCashCashEquivalentsAndAvailableForSaleInvestments_895538ce-b85d-48e1-a891-9cef8376f3cf" xlink:to="loc_us-gaap_InvestmentsFairValueDisclosure_0e3447dc-b083-4c97-b429-cfa570d0ee3c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Cash_cd294cc4-8c49-43a9-9572-8dc6e5b6e2e4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Cash"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_nktr_CashRestrictedCashCashEquivalentsAndAvailableForSaleInvestments_895538ce-b85d-48e1-a891-9cef8376f3cf" xlink:to="loc_us-gaap_Cash_cd294cc4-8c49-43a9-9572-8dc6e5b6e2e4" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.nektar.com/role/InventoryDetails" xlink:type="simple" xlink:href="nktr-20220630.xsd#InventoryDetails"/>
  <link:calculationLink xlink:role="http://www.nektar.com/role/InventoryDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNet_74033a47-34c9-47fe-9df6-2228e90258e3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InventoryNet"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryRawMaterialsNetOfReserves_fec973bc-5cf7-496d-bc05-58723b5063a2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InventoryRawMaterialsNetOfReserves"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_InventoryNet_74033a47-34c9-47fe-9df6-2228e90258e3" xlink:to="loc_us-gaap_InventoryRawMaterialsNetOfReserves_fec973bc-5cf7-496d-bc05-58723b5063a2" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryWorkInProcessNetOfReserves_a5b3d609-6333-4c5c-9641-a4d4d7d76301" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InventoryWorkInProcessNetOfReserves"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_InventoryNet_74033a47-34c9-47fe-9df6-2228e90258e3" xlink:to="loc_us-gaap_InventoryWorkInProcessNetOfReserves_a5b3d609-6333-4c5c-9641-a4d4d7d76301" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryFinishedGoodsNetOfReserves_8daa001f-6d35-4ca1-92d2-149bd97110cc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InventoryFinishedGoodsNetOfReserves"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_InventoryNet_74033a47-34c9-47fe-9df6-2228e90258e3" xlink:to="loc_us-gaap_InventoryFinishedGoodsNetOfReserves_8daa001f-6d35-4ca1-92d2-149bd97110cc" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.nektar.com/role/LiabilitiesRelatedtoSalesofFutureRoyaltiesActivityWithintheLiabilityAccountDetails" xlink:type="simple" xlink:href="nktr-20220630.xsd#LiabilitiesRelatedtoSalesofFutureRoyaltiesActivityWithintheLiabilityAccountDetails"/>
  <link:calculationLink xlink:role="http://www.nektar.com/role/LiabilitiesRelatedtoSalesofFutureRoyaltiesActivityWithintheLiabilityAccountDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesNonCurrentNetOfIssuanceCosts_cbe6465a-47ed-451a-b125-763b19a5e511" xlink:href="nktr-20220630.xsd#nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesNonCurrentNetOfIssuanceCosts"/>
    <link:loc xlink:type="locator" xlink:label="loc_nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesNonCurrent_63a44787-bcce-4171-9d3a-bd262cf77485" xlink:href="nktr-20220630.xsd#nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesNonCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesNonCurrentNetOfIssuanceCosts_cbe6465a-47ed-451a-b125-763b19a5e511" xlink:to="loc_nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesNonCurrent_63a44787-bcce-4171-9d3a-bd262cf77485" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nktr_LiabilitiesOnSaleOfFutureRoyaltiesUnamortizedTransactionCosts_77447c58-d1b9-476d-a9b9-1a83df85ef1a" xlink:href="nktr-20220630.xsd#nktr_LiabilitiesOnSaleOfFutureRoyaltiesUnamortizedTransactionCosts"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesNonCurrentNetOfIssuanceCosts_cbe6465a-47ed-451a-b125-763b19a5e511" xlink:to="loc_nktr_LiabilitiesOnSaleOfFutureRoyaltiesUnamortizedTransactionCosts_77447c58-d1b9-476d-a9b9-1a83df85ef1a" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.nektar.com/role/RestructuringImpairmentandOtherCostsofTerminatedProgramSummaryofRestructuringCostsDetails" xlink:type="simple" xlink:href="nktr-20220630.xsd#RestructuringImpairmentandOtherCostsofTerminatedProgramSummaryofRestructuringCostsDetails"/>
  <link:calculationLink xlink:role="http://www.nektar.com/role/RestructuringImpairmentandOtherCostsofTerminatedProgramSummaryofRestructuringCostsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostsAndAssetImpairmentCharges_54cc6215-f612-4f0a-9c61-2ad6a2160c14" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RestructuringCostsAndAssetImpairmentCharges"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetImpairmentCharges_124074db-c2c7-4035-8950-2c3060faea45" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetImpairmentCharges"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_RestructuringCostsAndAssetImpairmentCharges_54cc6215-f612-4f0a-9c61-2ad6a2160c14" xlink:to="loc_us-gaap_AssetImpairmentCharges_124074db-c2c7-4035-8950-2c3060faea45" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeveranceCosts1_8e54d303-93ae-42f3-8c6e-680a190b0d86" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SeveranceCosts1"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_RestructuringCostsAndAssetImpairmentCharges_54cc6215-f612-4f0a-9c61-2ad6a2160c14" xlink:to="loc_us-gaap_SeveranceCosts1_8e54d303-93ae-42f3-8c6e-680a190b0d86" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessExitCosts1_ec87349f-f28b-4937-9099-efdad929d720" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessExitCosts1"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_RestructuringCostsAndAssetImpairmentCharges_54cc6215-f612-4f0a-9c61-2ad6a2160c14" xlink:to="loc_us-gaap_BusinessExitCosts1_ec87349f-f28b-4937-9099-efdad929d720" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossOnContractTermination_58484869-07be-4120-8175-8fdc64eeb6f7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LossOnContractTermination"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_RestructuringCostsAndAssetImpairmentCharges_54cc6215-f612-4f0a-9c61-2ad6a2160c14" xlink:to="loc_us-gaap_LossOnContractTermination_58484869-07be-4120-8175-8fdc64eeb6f7" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.nektar.com/role/RestructuringImpairmentandOtherCostsofTerminatedProgramSubleaseInformationDetails" xlink:type="simple" xlink:href="nktr-20220630.xsd#RestructuringImpairmentandOtherCostsofTerminatedProgramSubleaseInformationDetails"/>
  <link:calculationLink xlink:role="http://www.nektar.com/role/RestructuringImpairmentandOtherCostsofTerminatedProgramSubleaseInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetImpairmentCharges_dc78dabf-b60f-479a-a2bb-9b25611e2a87" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetImpairmentCharges"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfLongLivedAssetsHeldForUse_96f99d38-d86d-46ba-a46e-ad5427c3e812" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ImpairmentOfLongLivedAssetsHeldForUse"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetImpairmentCharges_dc78dabf-b60f-479a-a2bb-9b25611e2a87" xlink:to="loc_us-gaap_ImpairmentOfLongLivedAssetsHeldForUse_96f99d38-d86d-46ba-a46e-ad5427c3e812" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseImpairmentLoss_17afc0e0-c2cd-4c18-843c-39ff0438f4b4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseImpairmentLoss"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetImpairmentCharges_dc78dabf-b60f-479a-a2bb-9b25611e2a87" xlink:to="loc_us-gaap_OperatingLeaseImpairmentLoss_17afc0e0-c2cd-4c18-843c-39ff0438f4b4" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.nektar.com/role/RestructuringImpairmentandOtherCostsofTerminatedProgramScheduleofPropertyPlantandEquipmentDetails" xlink:type="simple" xlink:href="nktr-20220630.xsd#RestructuringImpairmentandOtherCostsofTerminatedProgramScheduleofPropertyPlantandEquipmentDetails"/>
  <link:calculationLink xlink:role="http://www.nektar.com/role/RestructuringImpairmentandOtherCostsofTerminatedProgramScheduleofPropertyPlantandEquipmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_4a08cb26-07e5-4ba9-ac1a-83441c8c9a28" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_55e4c477-9dc7-4fc8-b351-ed957026b57a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet_4a08cb26-07e5-4ba9-ac1a-83441c8c9a28" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_55e4c477-9dc7-4fc8-b351-ed957026b57a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_140839b1-853f-4af0-831f-bd9b441f36b2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet_4a08cb26-07e5-4ba9-ac1a-83441c8c9a28" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_140839b1-853f-4af0-831f-bd9b441f36b2" xlink:type="arc"/>
  </link:calculationLink>
</link:linkbase>
