<XBRL>
<?xml version="1.0" encoding="US-ASCII"?>
<!--XBRL Document Created with WebFilings-->
<!-- -->
<linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <roleRef roleURI="http://www.fortinet.com/role/Acquisition" xlink:href="ftnt-20120930.xsd#Acquisition" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/AcquisitionDetails" xlink:href="ftnt-20120930.xsd#AcquisitionDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/CommitmentsAndContingencies" xlink:href="ftnt-20120930.xsd#CommitmentsAndContingencies" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/CommitmentsAndContingenciesLitigationDetails" xlink:href="ftnt-20120930.xsd#CommitmentsAndContingenciesLitigationDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/CommitmentsAndContingenciesOperatingLeasesDetails" xlink:href="ftnt-20120930.xsd#CommitmentsAndContingenciesOperatingLeasesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/CommitmentsAndContingenciesPurchaseCommitmentsDetails" xlink:href="ftnt-20120930.xsd#CommitmentsAndContingenciesPurchaseCommitmentsDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/CommitmentsAndContingenciesTables" xlink:href="ftnt-20120930.xsd#CommitmentsAndContingenciesTables" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/CommitmentsAndContingenciesWarrantiesDetails" xlink:href="ftnt-20120930.xsd#CommitmentsAndContingenciesWarrantiesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/CondensedConsolidatedBalanceSheets" xlink:href="ftnt-20120930.xsd#CondensedConsolidatedBalanceSheets" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/CondensedConsolidatedBalanceSheetsParenthetical" xlink:href="ftnt-20120930.xsd#CondensedConsolidatedBalanceSheetsParenthetical" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/CondensedConsolidatedStatementsOfCashFlows" xlink:href="ftnt-20120930.xsd#CondensedConsolidatedStatementsOfCashFlows" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/CondensedConsolidatedStatementsOfComprehensiveIncome" xlink:href="ftnt-20120930.xsd#CondensedConsolidatedStatementsOfComprehensiveIncome" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/CondensedConsolidatedStatementsOfOperations" xlink:href="ftnt-20120930.xsd#CondensedConsolidatedStatementsOfOperations" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/DeferredRevenues" xlink:href="ftnt-20120930.xsd#DeferredRevenues" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/DeferredRevenuesDetails" xlink:href="ftnt-20120930.xsd#DeferredRevenuesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/DeferredRevenuesTables" xlink:href="ftnt-20120930.xsd#DeferredRevenuesTables" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/DocumentAndEntityInformation" xlink:href="ftnt-20120930.xsd#DocumentAndEntityInformation" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/EmployeeBenefitPlan" xlink:href="ftnt-20120930.xsd#EmployeeBenefitPlan" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/EmployeeBenefitPlanDetails" xlink:href="ftnt-20120930.xsd#EmployeeBenefitPlanDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/ForeignCurrencyDerivatives" xlink:href="ftnt-20120930.xsd#ForeignCurrencyDerivatives" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/ForeignCurrencyDerivativesDetails" xlink:href="ftnt-20120930.xsd#ForeignCurrencyDerivativesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/ForeignCurrencyDerivativesTables" xlink:href="ftnt-20120930.xsd#ForeignCurrencyDerivativesTables" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/IncomeTaxes" xlink:href="ftnt-20120930.xsd#IncomeTaxes" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/IncomeTaxesDetails" xlink:href="ftnt-20120930.xsd#IncomeTaxesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/IntangibleAssets" xlink:href="ftnt-20120930.xsd#IntangibleAssets" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/IntangibleAssetsDetails" xlink:href="ftnt-20120930.xsd#IntangibleAssetsDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/IntangibleAssetsTables" xlink:href="ftnt-20120930.xsd#IntangibleAssetsTables" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/Inventory" xlink:href="ftnt-20120930.xsd#Inventory" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/InventoryDetails" xlink:href="ftnt-20120930.xsd#InventoryDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/InventoryTables" xlink:href="ftnt-20120930.xsd#InventoryTables" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/InvestmentAndFairValueMeasurements" xlink:href="ftnt-20120930.xsd#InvestmentAndFairValueMeasurements" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/InvestmentAndFairValueMeasurementsDetails" xlink:href="ftnt-20120930.xsd#InvestmentAndFairValueMeasurementsDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/InvestmentAndFairValueMeasurementsFairValueMeasurementsDetails" xlink:href="ftnt-20120930.xsd#InvestmentAndFairValueMeasurementsFairValueMeasurementsDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/InvestmentAndFairValueMeasurementsTables" xlink:href="ftnt-20120930.xsd#InvestmentAndFairValueMeasurementsTables" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/NetIncomePerShare" xlink:href="ftnt-20120930.xsd#NetIncomePerShare" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/NetIncomePerShareAntiDilutiveSecuritiesDetails" xlink:href="ftnt-20120930.xsd#NetIncomePerShareAntiDilutiveSecuritiesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/NetIncomePerShareCalculationOfBasicAndDilutedDetails" xlink:href="ftnt-20120930.xsd#NetIncomePerShareCalculationOfBasicAndDilutedDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/NetIncomePerShareTables" xlink:href="ftnt-20120930.xsd#NetIncomePerShareTables" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/PropertyAndEquipmentNet" xlink:href="ftnt-20120930.xsd#PropertyAndEquipmentNet" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/PropertyAndEquipmentNetDetails" xlink:href="ftnt-20120930.xsd#PropertyAndEquipmentNetDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/PropertyAndEquipmentNetTables" xlink:href="ftnt-20120930.xsd#PropertyAndEquipmentNetTables" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/SegmentAndSignificantCustomerInformation" xlink:href="ftnt-20120930.xsd#SegmentAndSignificantCustomerInformation" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/SegmentAndSignificantCustomerInformationCustomerConcentrationDetails" xlink:href="ftnt-20120930.xsd#SegmentAndSignificantCustomerInformationCustomerConcentrationDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/SegmentAndSignificantCustomerInformationDetails" xlink:href="ftnt-20120930.xsd#SegmentAndSignificantCustomerInformationDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/SegmentAndSignificantCustomerInformationTables" xlink:href="ftnt-20120930.xsd#SegmentAndSignificantCustomerInformationTables" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/StockholdersEquity" xlink:href="ftnt-20120930.xsd#StockholdersEquity" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/StockholdersEquityDetails" xlink:href="ftnt-20120930.xsd#StockholdersEquityDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/StockholdersEquityRsuActivityDetails" xlink:href="ftnt-20120930.xsd#StockholdersEquityRsuActivityDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/StockholdersEquitySharesAvailableForGrantDetails" xlink:href="ftnt-20120930.xsd#StockholdersEquitySharesAvailableForGrantDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/StockholdersEquityStockholdersEquityTables" xlink:href="ftnt-20120930.xsd#StockholdersEquityStockholdersEquityTables" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/SummaryOfSignificantAccountingPolicies" xlink:href="ftnt-20120930.xsd#SummaryOfSignificantAccountingPolicies" xlink:type="simple" />
  <roleRef roleURI="http://www.fortinet.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:href="ftnt-20120930.xsd#SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="simple" />
  <calculationLink xlink:role="http://www.fortinet.com/role/Acquisition" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/AcquisitionDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/CommitmentsAndContingencies" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/CommitmentsAndContingenciesLitigationDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/CommitmentsAndContingenciesOperatingLeasesDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/CommitmentsAndContingenciesPurchaseCommitmentsDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/CommitmentsAndContingenciesTables" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/CommitmentsAndContingenciesWarrantiesDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/CondensedConsolidatedBalanceSheets" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_fa7db8f6-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_f8ae30dc-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_fa7db8f6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_AssetsCurrent_f8ae30dc-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_e5378c74-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_f8ae30dc-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_e5378c74-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_e2791aa2-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_f8ae30dc-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_e2791aa2-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_ee7eb460-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_f8ae30dc-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_InventoryNet_ee7eb460-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DeferredTaxAssetsNetCurrent" xlink:label="loc_us-gaap_DeferredTaxAssetsNetCurrent_e77ca6c2-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="4" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_f8ae30dc-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_DeferredTaxAssetsNetCurrent_e77ca6c2-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssets" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssets_06ceefe4-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="5" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_f8ae30dc-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssets_06ceefe4-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShortTermInvestments" xlink:label="loc_us-gaap_ShortTermInvestments_f8083a06-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="6" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_f8ae30dc-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_ShortTermInvestments_f8083a06-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_f43e00ea-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_fa7db8f6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_f43e00ea-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DeferredTaxAssetsNetNoncurrent" xlink:label="loc_us-gaap_DeferredTaxAssetsNetNoncurrent_fb6cb6a4-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_fa7db8f6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_DeferredTaxAssetsNetNoncurrent_fb6cb6a4-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LongTermInvestments" xlink:label="loc_us-gaap_LongTermInvestments_efc96b8a-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="4" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_fa7db8f6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_LongTermInvestments_efc96b8a-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_ff39e37e-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="5" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_fa7db8f6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_ff39e37e-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_eed459d8-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_00bf81f4-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_eed459d8-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_StockholdersEquity_00bf81f4-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CommonStockValue" xlink:label="loc_us-gaap_CommonStockValue_e62cff4c-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_00bf81f4-2586-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_CommonStockValue_e62cff4c-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AdditionalPaidInCapitalCommonStock" xlink:label="loc_us-gaap_AdditionalPaidInCapitalCommonStock_e31bf3b2-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_00bf81f4-2586-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_AdditionalPaidInCapitalCommonStock_e31bf3b2-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_TreasuryStockValue" xlink:label="loc_us-gaap_TreasuryStockValue_fdef0d3c-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="3" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_00bf81f4-2586-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_TreasuryStockValue_fdef0d3c-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_e2cdfc7a-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="4" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_00bf81f4-2586-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_e2cdfc7a-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_f62c5e7e-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="5" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_00bf81f4-2586-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_f62c5e7e-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_eec8615a-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_eed459d8-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_Liabilities_eec8615a-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent_e70775a0-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_eec8615a-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_LiabilitiesCurrent_e70775a0-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaap_AccountsPayableCurrent_07c49f2a-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_e70775a0-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_AccountsPayableCurrent_07c49f2a-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_07f9742a-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_e70775a0-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_07f9742a-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_080122b0-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_e70775a0-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_080122b0-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DeferredRevenueCurrent" xlink:label="loc_us-gaap_DeferredRevenueCurrent_e81918b8-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="4" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_e70775a0-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_DeferredRevenueCurrent_e81918b8-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DeferredRevenueNoncurrent" xlink:label="loc_us-gaap_DeferredRevenueNoncurrent_e8195b34-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_eec8615a-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_DeferredRevenueNoncurrent_e8195b34-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_faebbfcc-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_eec8615a-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_faebbfcc-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://www.fortinet.com/role/CondensedConsolidatedBalanceSheetsParenthetical" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/CondensedConsolidatedStatementsOfCashFlows" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_f0b133d4-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0868ac6-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_f0b133d4-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0868ac6-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_f0af6c2a-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0868ac6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_NetIncomeLoss_f0af6c2a-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_05f0f9dc-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0868ac6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_05f0f9dc-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments" xlink:label="loc_us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_e28b34da-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="3" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0868ac6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_e28b34da-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaap_ShareBasedCompensation_eaf41c9a-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="4" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0868ac6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_ShareBasedCompensation_eaf41c9a-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities" xlink:label="loc_us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities_feb636d2-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="5" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0868ac6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities_feb636d2-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherNoncashIncomeExpense" xlink:label="loc_us-gaap_OtherNoncashIncomeExpense_0d51972c-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="6" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0868ac6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_OtherNoncashIncomeExpense_0d51972c-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_e5a3a9a4-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="7" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0868ac6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_e5a3a9a4-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInInventories" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories_e5ba7986-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="8" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0868ac6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_IncreaseDecreaseInInventories_e5ba7986-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredIncomeTaxes" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredIncomeTaxes_ff36a56a-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="9" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0868ac6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_IncreaseDecreaseInDeferredIncomeTaxes_ff36a56a-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_e5c99b5a-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="10" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0868ac6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_e5c99b5a-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets_ed9e60f4-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="11" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0868ac6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets_ed9e60f4-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayable_e5df5b16-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="12" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0868ac6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayable_e5df5b16-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInAccruedLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_e5e12d92-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="13" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0868ac6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_e5e12d92-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_e5ac2e76-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="14" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0868ac6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_e5ac2e76-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_ff60b206-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="15" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0868ac6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_ff60b206-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredRevenue" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredRevenue_ff36e7fa-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="16" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0868ac6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_IncreaseDecreaseInDeferredRevenue_ff36e7fa-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable_e5b73794-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="17" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0868ac6-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable_e5b73794-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_f085995e-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_f0b133d4-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_f085995e-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PaymentsToAcquireInvestments" xlink:label="loc_us-gaap_PaymentsToAcquireInvestments_f48d1d06-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_f085995e-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_PaymentsToAcquireInvestments_f48d1d06-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PaymentsToAcquireProductiveAssets" xlink:label="loc_us-gaap_PaymentsToAcquireProductiveAssets_e31f5b1a-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_f085995e-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_PaymentsToAcquireProductiveAssets_e31f5b1a-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_e2e2e6ee-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="3" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_f085995e-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_e2e2e6ee-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities" xlink:label="loc_us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities_f3fc2b5c-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="4" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_f085995e-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities_f3fc2b5c-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_GainLossOnSaleOfInvestments" xlink:label="loc_us-gaap_GainLossOnSaleOfInvestments_0db6c50c-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="5" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_f085995e-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_GainLossOnSaleOfInvestments_0db6c50c-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInRestrictedCash" xlink:label="loc_us-gaap_IncreaseDecreaseInRestrictedCash_eda673d4-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="6" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_f085995e-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_IncreaseDecreaseInRestrictedCash_eda673d4-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_f0848d20-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_f0b133d4-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_f0848d20-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:label="loc_us-gaap_ProceedsFromStockOptionsExercised_f43296ba-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_f0848d20-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_ProceedsFromStockOptionsExercised_f43296ba-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PaymentsOfStockIssuanceCosts" xlink:label="loc_us-gaap_PaymentsOfStockIssuanceCosts_f827062a-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_f0848d20-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_PaymentsOfStockIssuanceCosts_f827062a-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" xlink:label="loc_us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities_f88c5ffc-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_f0848d20-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities_f88c5ffc-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents" xlink:label="loc_us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents_ea0f1514-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="4" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_f0b133d4-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents_ea0f1514-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://www.fortinet.com/role/CondensedConsolidatedStatementsOfComprehensiveIncome" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_e63cc850-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_f0af6c2a-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax_e63cc850-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_NetIncomeLoss_f0af6c2a-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_081d6a92-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax_e63cc850-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_081d6a92-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToParent_07a7bfa4-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_081d6a92-2586-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToParent_07a7bfa4-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax_f1e10478-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_081d6a92-2586-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax_f1e10478-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesBeforeTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesBeforeTaxPortionAttributableToParent_08131128-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_081d6a92-2586-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesBeforeTaxPortionAttributableToParent_08131128-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent_0815e664-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="4" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_081d6a92-2586-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent_0815e664-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://www.fortinet.com/role/CondensedConsolidatedStatementsOfOperations" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SalesRevenueNet" xlink:label="loc_us-gaap_SalesRevenueNet_f679139a-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SalesRevenueGoodsNet" xlink:label="loc_us-gaap_SalesRevenueGoodsNet_f67a28d4-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_SalesRevenueNet_f679139a-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_SalesRevenueGoodsNet_f67a28d4-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SalesRevenueServicesNet" xlink:label="loc_us-gaap_SalesRevenueServicesNet_f67bca68-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_SalesRevenueNet_f679139a-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_SalesRevenueServicesNet_f67bca68-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="ftnt-20120930.xsd#ftnt_RatableAndOtherRevenueNet" xlink:label="loc_ftnt_RatableAndOtherRevenueNet_0b5c7c30-878a-b570-2abe-ea49ce325748" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_SalesRevenueNet_f679139a-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_ftnt_RatableAndOtherRevenueNet_0b5c7c30-878a-b570-2abe-ea49ce325748" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_f0af6c2a-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_ffc350a0-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_f0af6c2a-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_ffc350a0-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_f1959cb8-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_ffc350a0-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_OperatingIncomeLoss_f1959cb8-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaap_GrossProfit_ec7be2aa-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_f1959cb8-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_GrossProfit_ec7be2aa-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="ftnt-20120930.xsd#ftnt_ProductGrossProfit" xlink:label="loc_ftnt_ProductGrossProfit_952600f9-ac19-5f10-6649-ea49c947c423" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit_ec7be2aa-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_ftnt_ProductGrossProfit_952600f9-ac19-5f10-6649-ea49c947c423" xlink:type="arc" />
    <loc xlink:href="ftnt-20120930.xsd#ftnt_ServicesGrossProfit" xlink:label="loc_ftnt_ServicesGrossProfit_e6f87533-5573-94db-6199-ea49d238fd10" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit_ec7be2aa-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_ftnt_ServicesGrossProfit_e6f87533-5573-94db-6199-ea49d238fd10" xlink:type="arc" />
    <loc xlink:href="ftnt-20120930.xsd#ftnt_RatableAndOtherRevenueGrossProfit" xlink:label="loc_ftnt_RatableAndOtherRevenueGrossProfit_f2a1a403-cba2-b877-f27f-ea49ce3aa53b" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit_ec7be2aa-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_ftnt_RatableAndOtherRevenueGrossProfit_f2a1a403-cba2-b877-f27f-ea49ce3aa53b" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OperatingExpenses" xlink:label="loc_us-gaap_OperatingExpenses_ff41c85a-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_f1959cb8-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_OperatingExpenses_ff41c85a-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_f9ff4160-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses_ff41c85a-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_f9ff4160-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SellingAndMarketingExpense" xlink:label="loc_us-gaap_SellingAndMarketingExpense_f7784e32-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses_ff41c85a-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_SellingAndMarketingExpense_f7784e32-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_ec692278-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses_ff41c85a-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_ec692278-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InvestmentIncomeNet" xlink:label="loc_us-gaap_InvestmentIncomeNet_ee8cd1a8-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_ffc350a0-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_InvestmentIncomeNet_ee8cd1a8-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_f0eb70ee-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_ffc350a0-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_f0eb70ee-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_0106fc64-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_f0af6c2a-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_0106fc64-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CostOfGoodsAndServicesSold" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_e6cc9390-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CostOfGoodsSold" xlink:label="loc_us-gaap_CostOfGoodsSold_e6ce98a2-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CostOfGoodsAndServicesSold_e6cc9390-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_CostOfGoodsSold_e6ce98a2-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CostOfServices" xlink:label="loc_us-gaap_CostOfServices_e6e497d8-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CostOfGoodsAndServicesSold_e6cc9390-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_CostOfServices_e6e497d8-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="ftnt-20120930.xsd#ftnt_CostOfRatableAndOtherRevenue" xlink:label="loc_ftnt_CostOfRatableAndOtherRevenue_d5926261-62e2-81cf-70ed-ea49d23d7324" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CostOfGoodsAndServicesSold_e6cc9390-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_ftnt_CostOfRatableAndOtherRevenue_d5926261-62e2-81cf-70ed-ea49d23d7324" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://www.fortinet.com/role/DeferredRevenues" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/DeferredRevenuesDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DeferredRevenue" xlink:label="loc_us-gaap_DeferredRevenue_ff39051c-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DeferredRevenueCurrent" xlink:label="loc_us-gaap_DeferredRevenueCurrent_e81918b8-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_DeferredRevenue_ff39051c-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_DeferredRevenueCurrent_e81918b8-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DeferredRevenueNoncurrent" xlink:label="loc_us-gaap_DeferredRevenueNoncurrent_e8195b34-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_DeferredRevenue_ff39051c-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_DeferredRevenueNoncurrent_e8195b34-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://www.fortinet.com/role/DeferredRevenuesTables" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/DocumentAndEntityInformation" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/EmployeeBenefitPlan" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/EmployeeBenefitPlanDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/ForeignCurrencyDerivatives" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/ForeignCurrencyDerivativesDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/ForeignCurrencyDerivativesTables" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/IncomeTaxes" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/IncomeTaxesDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/IntangibleAssets" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/IntangibleAssetsDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_edd1cd86-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_edd0f4f6-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet_edd1cd86-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_edd0f4f6-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_e2cbd8dc-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet_edd1cd86-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_e2cbd8dc-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpense" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpense_eba7bac0-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FutureAmortizationExpenseYearOne" xlink:label="loc_us-gaap_FutureAmortizationExpenseYearOne_ec1ea068-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpense_eba7bac0-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_FutureAmortizationExpenseYearOne_ec1ea068-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FutureAmortizationExpenseYearTwo" xlink:label="loc_us-gaap_FutureAmortizationExpenseYearTwo_ec2018e4-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpense_eba7bac0-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_FutureAmortizationExpenseYearTwo_ec2018e4-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FutureAmortizationExpenseYearThree" xlink:label="loc_us-gaap_FutureAmortizationExpenseYearThree_ec1f5d28-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpense_eba7bac0-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_FutureAmortizationExpenseYearThree_ec1f5d28-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FutureAmortizationExpenseRemainderOfFiscalYear" xlink:label="loc_us-gaap_FutureAmortizationExpenseRemainderOfFiscalYear_08faad26-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="4" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpense_eba7bac0-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_FutureAmortizationExpenseRemainderOfFiscalYear_08faad26-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FutureAmortizationExpenseYearFour" xlink:label="loc_us-gaap_FutureAmortizationExpenseYearFour_ec1e00e0-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="5" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpense_eba7bac0-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_FutureAmortizationExpenseYearFour_ec1e00e0-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://www.fortinet.com/role/IntangibleAssetsTables" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/Inventory" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/InventoryDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_ee7eb460-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InventoryRawMaterialsNetOfReserves" xlink:label="loc_us-gaap_InventoryRawMaterialsNetOfReserves_04189ae8-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_InventoryNet_ee7eb460-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_InventoryRawMaterialsNetOfReserves_04189ae8-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InventoryFinishedGoodsNetOfReserves" xlink:label="loc_us-gaap_InventoryFinishedGoodsNetOfReserves_0416e95a-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_InventoryNet_ee7eb460-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_InventoryFinishedGoodsNetOfReserves_0416e95a-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://www.fortinet.com/role/InventoryTables" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/InvestmentAndFairValueMeasurements" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/InvestmentAndFairValueMeasurementsDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_fa29568a-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_0bde83f0-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_fa29568a-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_0bde83f0-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableforsaleSecuritiesGrossUnrealizedGain" xlink:label="loc_us-gaap_AvailableforsaleSecuritiesGrossUnrealizedGain_09db1640-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_fa29568a-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_AvailableforsaleSecuritiesGrossUnrealizedGain_09db1640-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableForSaleSecuritiesGrossUnrealizedLosses1" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesGrossUnrealizedLosses1_0d531534-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="3" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_fa29568a-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesGrossUnrealizedLosses1_0d531534-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableforsaleSecuritiesContinuousUnrealizedLossPositionAggregateLosses1" xlink:label="loc_us-gaap_AvailableforsaleSecuritiesContinuousUnrealizedLossPositionAggregateLosses1_0eae1e2e-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableforsaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses1" xlink:label="loc_us-gaap_AvailableforsaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses1_0ead980a-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AvailableforsaleSecuritiesContinuousUnrealizedLossPositionAggregateLosses1_0eae1e2e-2586-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_AvailableforsaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses1_0ead980a-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableforsaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses1" xlink:label="loc_us-gaap_AvailableforsaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses1_0ead17f4-2586-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AvailableforsaleSecuritiesContinuousUnrealizedLossPositionAggregateLosses1_0eae1e2e-2586-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_AvailableforsaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses1_0ead17f4-2586-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue_fa23c01c-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue_fa232bd4-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue_fa23c01c-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue_fa232bd4-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue_fa22b83e-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue_fa23c01c-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue_fa22b83e-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://www.fortinet.com/role/InvestmentAndFairValueMeasurementsFairValueMeasurementsDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/InvestmentAndFairValueMeasurementsTables" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/NetIncomePerShare" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/NetIncomePerShareAntiDilutiveSecuritiesDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/NetIncomePerShareCalculationOfBasicAndDilutedDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/NetIncomePerShareTables" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/PropertyAndEquipmentNet" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/PropertyAndEquipmentNetDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_f43e00ea-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_f43d4286-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet_f43e00ea-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_f43d4286-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_e2d13566-2585-11e0-bc05-7b821c07cce9" xlink:type="locator" />
    <calculationArc order="2" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet_f43e00ea-2585-11e0-bc05-7b821c07cce9" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_e2d13566-2585-11e0-bc05-7b821c07cce9" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://www.fortinet.com/role/PropertyAndEquipmentNetTables" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/SegmentAndSignificantCustomerInformation" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/SegmentAndSignificantCustomerInformationCustomerConcentrationDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/SegmentAndSignificantCustomerInformationDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/SegmentAndSignificantCustomerInformationTables" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/StockholdersEquity" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/StockholdersEquityDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/StockholdersEquityRsuActivityDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/StockholdersEquitySharesAvailableForGrantDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/StockholdersEquityStockholdersEquityTables" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/SummaryOfSignificantAccountingPolicies" xlink:type="extended" />
  <calculationLink xlink:role="http://www.fortinet.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="extended" />
</linkbase>
</XBRL>
