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   <sob:IdentificationOfApprovedAnnualReport contextRef="D0"> The Board of Directors and the Executive Board have today discussed and approved the  annual report for GARTNER DANMARK ApS for the financial year 1 January - 31 December 2025.</sob:IdentificationOfApprovedAnnualReport>
   <sob:ConfirmationThatAnnualReportIsPresentedInAccordanceWithRequirementsProvidedForByLegislationAnyStandardsAndRequirementsProvidedByArticlesOfAssociationOrByAgreement contextRef="D0"> The  annual report has been prepared in accordance with the Danish Financial Statements Act.</sob:ConfirmationThatAnnualReportIsPresentedInAccordanceWithRequirementsProvidedForByLegislationAnyStandardsAndRequirementsProvidedByArticlesOfAssociationOrByAgreement>
   <sob:ConfirmationThatFinancialStatementGivesTrueAndFairViewOfAssetsLiabilitiesEquityFinancialPositionAndResults contextRef="D0"> In our opinion, the  financial statements give a true and fair view of the Company's assets, liabilities and financial position at 31 December 2025 and of the results of the Company's operations for the financial year 1 January - 31 December 2025.</sob:ConfirmationThatFinancialStatementGivesTrueAndFairViewOfAssetsLiabilitiesEquityFinancialPositionAndResults>
   <sob:ManagementsStatementAboutManagementsReview contextRef="D0"> Further, in our opinion, the Management's review gives a fair review of the development in the Company's activities and financial matters, of the results for the year and of the Company's financial position.</sob:ManagementsStatementAboutManagementsReview>
   <sob:RecommendationForApprovalOfAnnualReportByGeneralMeeting contextRef="D0"> We recommend that the annual report be approved at the annual general meeting.</sob:RecommendationForApprovalOfAnnualReportByGeneralMeeting>
   <sob:PlaceOfSignatureOfStatement contextRef="D0">Hellerup</sob:PlaceOfSignatureOfStatement>
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   <cmn:NameAndSurnameOfMemberOfSupervisoryBoard contextRef="D2">Paola Farina</cmn:NameAndSurnameOfMemberOfSupervisoryBoard>
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   <cmn:NameAndSurnameOfMemberOfSupervisoryBoard contextRef="D3">Elin Gaare Ronesen</cmn:NameAndSurnameOfMemberOfSupervisoryBoard>
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   <cmn:NameAndSurnameOfMemberOfSupervisoryBoard contextRef="D4">Brooke Bare Clark</cmn:NameAndSurnameOfMemberOfSupervisoryBoard>
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   <arr:IndependentAuditorsReportsAudit contextRef="D0" xml:lang="en">Independent auditor's report</arr:IndependentAuditorsReportsAudit>
   <arr:AddresseeOfAuditorsReportOnAuditedFinancialStatements contextRef="D0" xml:lang="en">To the shareholder of GARTNER DANMARK ApS</arr:AddresseeOfAuditorsReportOnAuditedFinancialStatements>
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   <arr:OpinionOnAuditedFinancialStatements contextRef="D0" xml:lang="en">We have audited the financial statements of GARTNER DANMARK ApS for the financial year 1 January - 31 December 2025, comprising income statement, balance sheet, statement of changes in equity and notes, including accounting policies. The financial statements are prepared in accordance with the Danish Financial Statements Act. In our opinion, the financial statements give a true and fair view of the Company's assets, liabilities and financial position at 31 December 2025 and of the results of the Company's operations  for the financial year 1 January - 31 December 2025 in accordance with the Danish Financial Statements Act.</arr:OpinionOnAuditedFinancialStatements>
   <arr:TypeOfBasisForModifiedOpinionOnAuditedFinancialStatements contextRef="D0" xml:lang="en">Basis for Opinion</arr:TypeOfBasisForModifiedOpinionOnAuditedFinancialStatements>
   <arr:DescriptionOfQualificationsOfAuditedFinancialStatements contextRef="D0" xml:lang="en">We conducted our audit in accordance with International Standards on Auditing (ISAs) and the additional requirements applicable in Denmark. Our responsibilities under those standards and requirements are further described in the "Auditor's responsibilities for the audit of the financial statements" section of our report.We are independent of the Company in accordance with the International Ethics Standards Board for Accountants' International Code of Ethics for Professional Accountants (IESBA Code) and the additional ethical requirements applicable in Denmark, and we have fulfilled our other ethical responsibilities in accordance with these requirements and the IESBA Code. We believe that the audit evidence we have obtained is sufficient and appropriate to provide a basis for our opinion.</arr:DescriptionOfQualificationsOfAuditedFinancialStatements>
   <arr:StatementOfExecutiveAndSupervisoryBoardsResponsibilityForFinancialStatements contextRef="D0" xml:lang="en">Management's responsibility for the financial statementsManagement is responsible for the preparation of financial statements that give a true and fair view in accordance with the Danish Financial Statements Act and for such internal control that Management determines is necessary to enable the preparation of financial statements that are free from material misstatement, whether due to fraud or error. In preparing the financial statements, Management is responsible for assessing the Company's ability to continue as a going concern, disclosing, as applicable, matters related to going concern and using the going concern basis of accounting in preparing the financial statements unless Management either intends to liquidate the Company or to cease operations, or has no realistic alternative but to do so.</arr:StatementOfExecutiveAndSupervisoryBoardsResponsibilityForFinancialStatements>
   <arr:StatementOfAuditorsResponsibilityForAuditAndAuditPerformed contextRef="D0" xml:lang="en">Auditor's responsibilities for the audit of the financial statementsOur objectives are to obtain reasonable assurance as to whether the financial statements as a whole are free from material misstatement, whether due to fraud or error, and to issue an auditor's report that includes our opinion. Reasonable assurance is a high level of assurance but is not a guarantee that an audit conducted in accordance with ISAs and the additional requirements in Denmark will always detect a material misstatement when it exists. Misstatements may arise from fraud or error and are considered material if, individually or in the aggregate, they could reasonably be expected to influence the economic decisions of financial statement users made on the basis of these financial statements.As part of an audit conducted in accordance with ISAs and the additional requirements applicable in Denmark, we exercise professional judgement and maintain professional scepticism throughout the audit. We alsoidentify and assess the risks of material misstatement of the company financial statements, whether due to fraud or error, design and perform audit procedures responsive to those risks, and obtain audit evidence that is sufficient and appropriate to provide a basis for our opinion. The risk of not detecting a material misstatement resulting from fraud is higher than for one resulting from error as fraud may involve collusion, forgery, intentional omissions, misrepresentations or the override of internal control.obtain an understanding of internal control relevant to the audit in order to design audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Company's internal control.evaluate the appropriateness of accounting policies used and the reasonableness of accounting estimates and related disclosures made by Management.conclude on the appropriateness of Management's use of the going concern basis of accounting in preparing the financial statements and, based on the audit evidence obtained, whether a material uncertainty exists related to events or conditions that may cast significant doubt on the Company's ability to continue as a going concern. If we conclude that a material uncertainty exists, we are required to draw attention in our auditor's report to the related disclosures in the financial statements or, if such disclosures are inadequate, to modify our opinion. Our conclusions are based on the audit evidence obtained up to the date of our auditor's report. However, future events or conditions may cause the Company to cease to continue as a going concern.evaluate the overall presentation, structure and contents of the financial statements, including the disclosures, and whether the financial statements represent the underlying transactions and events in a manner that gives a true and fair view.We communicate with those charged with governance regarding, among other matters, the planned scope and timing of the audit and significant audit findings, including any significant deficiencies in internal control that we identify during our audit.</arr:StatementOfAuditorsResponsibilityForAuditAndAuditPerformed>
   <arr:StatementOnManagementsReviewAuditorsReportOnAuditedFinancialStatements contextRef="D0" xml:lang="en">Statement on the Management's reviewManagement is responsible for the Management's review.Our opinion on the financial statements does not cover the Management's review, and we do not express any form of assurance conclusion thereon.In connection with our audit of the financial statements, our responsibility is to read the Management's review and, in doing so, consider whether the Management's review is materially inconsistent with the financial statements or our knowledge obtained during the audit, or otherwise appears to be materially misstated.Moreover, it is our responsibility to consider whether the Management's review provides the information required under the Danish Financial Statements Act. Based on the work we have performed, we conclude that the Management's review is in accordance with the financial statements and has been prepared in accordance with the requirements of the Danish Financial Statement Act. We did not identify any material misstatement of the Management's review.</arr:StatementOnManagementsReviewAuditorsReportOnAuditedFinancialStatements>
   <arr:SignatureOfAuditorsPlace contextRef="D0">Aarhus</arr:SignatureOfAuditorsPlace>
   <arr:SignatureOfAuditorsDate contextRef="D0">2026-05-21</arr:SignatureOfAuditorsDate>
   <cmn:NameOfAuditFirm contextRef="D5">KPMG </cmn:NameOfAuditFirm>
   <cmn:IdentificationNumberCvrOfAuditFirm contextRef="D5">25578198</cmn:IdentificationNumberCvrOfAuditFirm>
   <cmn:NameAndSurnameOfAuditor contextRef="D5">Niklas R. Filipsen</cmn:NameAndSurnameOfAuditor>
   <cmn:DescriptionOfAuditor contextRef="D5" xml:lang="en">State Authorised Public Accountant</cmn:DescriptionOfAuditor>
   <cmn:IdentificationNumberOfAuditor contextRef="D5">mne47781</cmn:IdentificationNumberOfAuditor>
   <gsd:NameOfReportingEntity contextRef="D0"> GARTNER DANMARK ApS</gsd:NameOfReportingEntity>
   <gsd:AddressOfReportingEntityStreetName contextRef="D0"> Philip Heymans Alle </gsd:AddressOfReportingEntityStreetName>
   <gsd:AddressOfReportingEntityStreetBuildingIdentifier contextRef="D0"> 7</gsd:AddressOfReportingEntityStreetBuildingIdentifier>
   <gsd:AddressOfReportingEntityPostCodeIdentifier contextRef="D0"> DK-2900  </gsd:AddressOfReportingEntityPostCodeIdentifier>
   <gsd:AddressOfReportingEntityDistrictName contextRef="D0"> Hellerup</gsd:AddressOfReportingEntityDistrictName>
   <gsd:TelephoneNumberOfReportingEntity contextRef="D0"> 45 58 64 00</gsd:TelephoneNumberOfReportingEntity>
   <gsd:HomepageOfReportingEntity contextRef="D0"> www.gartner.com</gsd:HomepageOfReportingEntity>
   <gsd:IdentificationNumberCvrOfSubmittingEnterprise contextRef="D0">12516835</gsd:IdentificationNumberCvrOfSubmittingEnterprise>
   <gsd:DateOfFoundationOfReportingEntity contextRef="D0" xml:lang="en">1988-09-01</gsd:DateOfFoundationOfReportingEntity>
   <gsd:RegisteredOfficeOfReportingEntity contextRef="D0"> Gentofte</gsd:RegisteredOfficeOfReportingEntity>
   <gsd:ReportingPeriodStartDate contextRef="D0" xml:lang="en">2025-01-01</gsd:ReportingPeriodStartDate>
   <gsd:ReportingPeriodEndDate contextRef="D0" xml:lang="en">2025-12-31</gsd:ReportingPeriodEndDate>
   <cmn:NameOfAuditFirm contextRef="D0">KPMG</cmn:NameOfAuditFirm>
   <cmn:DescriptionOfAuditor contextRef="D0">Statsautoriseret Revisionspartnerselskab</cmn:DescriptionOfAuditor>
   <gsd:AddressOfAuditorStreetName contextRef="D0">Frederiks Plads </gsd:AddressOfAuditorStreetName>
   <gsd:AddressOfAuditorStreetBuildingIdentifier contextRef="D0">42 </gsd:AddressOfAuditorStreetBuildingIdentifier>
   <gsd:AddressOfAuditorPostCodeIdentifier contextRef="D0">8000 </gsd:AddressOfAuditorPostCodeIdentifier>
   <gsd:AddressOfAuditorDistrictName contextRef="D0">Aarhus C</gsd:AddressOfAuditorDistrictName>
   <cmn:IdentificationNumberCvrOfAuditFirm contextRef="D0">25578198</cmn:IdentificationNumberCvrOfAuditFirm>
   <fsa:GrossProfitLoss contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">129991000</fsa:GrossProfitLoss>
   <fsa:GrossProfitLoss contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">128574000</fsa:GrossProfitLoss>
   <fsa:GrossProfitLoss contextRef="D7" decimals="-3" unitRef="U-iso4217-DKK">107779000</fsa:GrossProfitLoss>
   <fsa:GrossProfitLoss contextRef="D8" decimals="-3" unitRef="U-iso4217-DKK">117499000</fsa:GrossProfitLoss>
   <fsa:GrossProfitLoss contextRef="D9" decimals="-3" unitRef="U-iso4217-DKK">93478000</fsa:GrossProfitLoss>
   <fsa:ProfitLossFromOrdinaryOperatingActivities contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">4807000</fsa:ProfitLossFromOrdinaryOperatingActivities>
   <fsa:ProfitLossFromOrdinaryOperatingActivities contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">7559000</fsa:ProfitLossFromOrdinaryOperatingActivities>
   <fsa:ProfitLossFromOrdinaryOperatingActivities contextRef="D7" decimals="-3" unitRef="U-iso4217-DKK">9508000</fsa:ProfitLossFromOrdinaryOperatingActivities>
   <fsa:ProfitLossFromOrdinaryOperatingActivities contextRef="D8" decimals="-3" unitRef="U-iso4217-DKK">16679000</fsa:ProfitLossFromOrdinaryOperatingActivities>
   <fsa:ProfitLossFromOrdinaryOperatingActivities contextRef="D9" decimals="-3" unitRef="U-iso4217-DKK">3300000</fsa:ProfitLossFromOrdinaryOperatingActivities>
   <fsa:ResultsFromNetFinancials contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">1927000</fsa:ResultsFromNetFinancials>
   <fsa:ResultsFromNetFinancials contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">2967000</fsa:ResultsFromNetFinancials>
   <fsa:ResultsFromNetFinancials contextRef="D7" decimals="-3" unitRef="U-iso4217-DKK">1140000</fsa:ResultsFromNetFinancials>
   <fsa:ResultsFromNetFinancials contextRef="D8" decimals="-3" unitRef="U-iso4217-DKK">53000</fsa:ResultsFromNetFinancials>
   <fsa:ResultsFromNetFinancials contextRef="D9" decimals="-3" unitRef="U-iso4217-DKK">-141000</fsa:ResultsFromNetFinancials>
   <fsa:ProfitLoss contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">5168000</fsa:ProfitLoss>
   <fsa:ProfitLoss contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">8141000</fsa:ProfitLoss>
   <fsa:ProfitLoss contextRef="D7" decimals="-3" unitRef="U-iso4217-DKK">8239000</fsa:ProfitLoss>
   <fsa:ProfitLoss contextRef="D8" decimals="-3" unitRef="U-iso4217-DKK">13009000</fsa:ProfitLoss>
   <fsa:ProfitLoss contextRef="D9" decimals="-3" unitRef="U-iso4217-DKK">2418000</fsa:ProfitLoss>
   <fsa:Assets contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">214536000</fsa:Assets>
   <fsa:Assets contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">227953000</fsa:Assets>
   <fsa:Assets contextRef="I2" decimals="-3" unitRef="U-iso4217-DKK">197626000</fsa:Assets>
   <fsa:Assets contextRef="I3" decimals="-3" unitRef="U-iso4217-DKK">172496000</fsa:Assets>
   <fsa:Assets contextRef="I4" decimals="-3" unitRef="U-iso4217-DKK">166137000</fsa:Assets>
   <fsa:InvestmentInPropertyPlantAndEquipment contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">1580000</fsa:InvestmentInPropertyPlantAndEquipment>
   <fsa:InvestmentInPropertyPlantAndEquipment contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">108000</fsa:InvestmentInPropertyPlantAndEquipment>
   <fsa:InvestmentInPropertyPlantAndEquipment contextRef="D7" decimals="-3" unitRef="U-iso4217-DKK">0</fsa:InvestmentInPropertyPlantAndEquipment>
   <fsa:InvestmentInPropertyPlantAndEquipment contextRef="D8" decimals="-3" unitRef="U-iso4217-DKK">84000</fsa:InvestmentInPropertyPlantAndEquipment>
   <fsa:InvestmentInPropertyPlantAndEquipment contextRef="D9" decimals="-3" unitRef="U-iso4217-DKK">119000</fsa:InvestmentInPropertyPlantAndEquipment>
   <fsa:Equity contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">50279000</fsa:Equity>
   <fsa:Equity contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">45111000</fsa:Equity>
   <fsa:Equity contextRef="I2" decimals="-3" unitRef="U-iso4217-DKK">36970000</fsa:Equity>
   <fsa:Equity contextRef="I3" decimals="-3" unitRef="U-iso4217-DKK">28731000</fsa:Equity>
   <fsa:Equity contextRef="I4" decimals="-3" unitRef="U-iso4217-DKK">18122000</fsa:Equity>
   <mrv:EquityRatio contextRef="D0" decimals="4" unitRef="U-pure">1080</mrv:EquityRatio>
   <mrv:EquityRatio contextRef="D6" decimals="4" unitRef="U-pure">1980</mrv:EquityRatio>
   <mrv:EquityRatio contextRef="D7" decimals="4" unitRef="U-pure">2510</mrv:EquityRatio>
   <mrv:EquityRatio contextRef="D8" decimals="4" unitRef="U-pure">5550</mrv:EquityRatio>
   <mrv:EquityRatio contextRef="D9" decimals="4" unitRef="U-pure">1120</mrv:EquityRatio>
   <mrv:SolvencyRatio contextRef="D0" decimals="4" unitRef="U-pure">2340</mrv:SolvencyRatio>
   <mrv:SolvencyRatio contextRef="D6" decimals="4" unitRef="U-pure">1980</mrv:SolvencyRatio>
   <mrv:SolvencyRatio contextRef="D7" decimals="4" unitRef="U-pure">1870</mrv:SolvencyRatio>
   <mrv:SolvencyRatio contextRef="D8" decimals="4" unitRef="U-pure">1670</mrv:SolvencyRatio>
   <mrv:SolvencyRatio contextRef="D9" decimals="4" unitRef="U-pure">1090</mrv:SolvencyRatio>
   <fsa:AverageNumberOfEmployees contextRef="D0" decimals="-3" unitRef="U-pure">51000</fsa:AverageNumberOfEmployees>
   <fsa:AverageNumberOfEmployees contextRef="D6" decimals="-3" unitRef="U-pure">52000</fsa:AverageNumberOfEmployees>
   <fsa:AverageNumberOfEmployees contextRef="D7" decimals="-3" unitRef="U-pure">52000</fsa:AverageNumberOfEmployees>
   <fsa:AverageNumberOfEmployees contextRef="D8" decimals="-3" unitRef="U-pure">53000</fsa:AverageNumberOfEmployees>
   <fsa:AverageNumberOfEmployees contextRef="D9" decimals="-3" unitRef="U-pure">51000</fsa:AverageNumberOfEmployees>
   <mrv:InformationOnCalculationOfKeyFiguresAndFinancialRatios contextRef="D0">The financial ratios have been calculated as follows:Return on equityProfit/loss after tax x 100 / Average equitySolvency ratioEquity at year end x 100 / Total equity and liabilities at year end</mrv:InformationOnCalculationOfKeyFiguresAndFinancialRatios>
   <mrv:DescriptionOfPrimaryActivitiesOfEntity contextRef="D0" xml:lang="en"> Principal activities                                   Gartner Danmark ApS is part of the multinational group Gartner, Inc. (NYSE: IT), which delivers actionable, objective business and technology insights that drive smarter decisions and stronger performance on an organisation’s mission-critical priorities.                                  Gartner is a trusted advisor and an objective resource for over 13,000 entities in approximately 90 countries and territories— across every major function, geography, industry and sector.                                  Gartner delivers its products and services globally through three reportable segments – Business and Technology Insights, Conferences and Consulting as described below. In the second quarter of 2025, we renamed our segment previously referred to as Research to Business and Technology Insights (or “Insights”) to reflect the nature of the value we provide to clients.                                  Insights equip executives and their teams from every major function, geography, industry and sector with actionable, objective insights, guidance and tools. Our experts deliver proprietary insights that are informed by thoroughly vetted practitioner sourced and data-driven research to help our clients address their mission-critical priorities.                                  Conferences provides executives and teams across an organisation with the opportunity to learn, share and network. From our Gartner Symposium/Xpo series, to industry-leading conferences focused on specific business roles and topics, to peer-driven sessions, our offerings enable attendees to experience the best of Gartner insights and guidance.                                  Consulting serves senior executives leading technology-driven strategic initiatives leveraging the power of Gartner’s actionable, objective insights. Through custom analysis and on-the-ground support, we enable optimised technology investments and stronger performance on our clients’ mission-critical priorities.</mrv:DescriptionOfPrimaryActivitiesOfEntity>
   <mrv:DescriptionOfDevelopmentInActivitiesAndFinancialAffairs contextRef="D0" xml:lang="en"> Development in activities and financial position  Profit for the year (including comparison with outlook previously announced)                                   The Company's income statement for 2025 shows a profit of DKK 5,168 thousand as against a profit of DKK 8,141 thousand in 2024. Equity in the Company's balance sheet at 31 December 2025 stood at DKK 50,279 thousand as against DKK 45,111 thousand at 31 December 2024.                                  Profit for the year amounted to DKK 5,168 thousand, which was below forecast profit range of DKK 8,000–10,000 thousand. This variance was attributable to lower interest rates and non-recurring costs. Overall, performance is considered satisfactory and broadly in line with expectations.</mrv:DescriptionOfDevelopmentInActivitiesAndFinancialAffairs>
   <mrv:DescriptionOfExpectedDevelopment contextRef="D0" xml:lang="en"> Outlook                                   The Company continues to work in a hybrid virtual-first working environment, which provides additional flexibility to employees, enabling most of them to work remotely a substantial portion of the time. The Company also provides a number of free mental and behavioral health resources, including access to the Employee Assistance Program for employees and their dependents.                                  The Company is confident that the qualitative level of its analyzes and research, its long-standing established brand in the sector, its organisational and business model will be able to consolidate its market shares and its revenue. For 2026, the Company expects profit for the year in the range of DKK 5,000-10,000 thousand.</mrv:DescriptionOfExpectedDevelopment>
   <mrv:EntitysObjectivesAndPolitiesForFinancialRiskManagement contextRef="D0" xml:lang="en"> Financial instruments  The Company's goals and policies for management of financial risks                                   Operating risks:
                  The Company is not exposed to any particular risks apart from usual operating risks within our business.                                  Financial risks:
                  As a result of its business, the Company is exposed to changes in exchange rates and interest rate levels. The Parent Group controls financial risks in the Group centrally and coordinates cash management.</mrv:EntitysObjectivesAndPolitiesForFinancialRiskManagement>
   <mrv:DescriptionOfSignificantEventsOccurringAfterEndOfReportingPeriod contextRef="D0" xml:lang="en"> Events after the balance sheet date                                   No events have occurred after the balance sheet date of material importance to the annual report for 2025.</mrv:DescriptionOfSignificantEventsOccurringAfterEndOfReportingPeriod>
   <fsa:GrossProfitLoss contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">129991000</fsa:GrossProfitLoss>
   <fsa:GrossProfitLoss contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">128574000</fsa:GrossProfitLoss>
   <fsa:EmployeeBenefitsExpense contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">125019000</fsa:EmployeeBenefitsExpense>
   <fsa:EmployeeBenefitsExpense contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">120858000</fsa:EmployeeBenefitsExpense>
   <fsa:DepreciationAmortisationExpenseAndImpairmentLossesOfPropertyPlantAndEquipmentAndIntangibleAssetsRecognisedInProfitOrLoss contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">165000</fsa:DepreciationAmortisationExpenseAndImpairmentLossesOfPropertyPlantAndEquipmentAndIntangibleAssetsRecognisedInProfitOrLoss>
   <fsa:DepreciationAmortisationExpenseAndImpairmentLossesOfPropertyPlantAndEquipmentAndIntangibleAssetsRecognisedInProfitOrLoss contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">157000</fsa:DepreciationAmortisationExpenseAndImpairmentLossesOfPropertyPlantAndEquipmentAndIntangibleAssetsRecognisedInProfitOrLoss>
   <fsa:ProfitLossFromOrdinaryOperatingActivitiesBeforeGainsLossesFromFairValueAdjustments contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">4807000</fsa:ProfitLossFromOrdinaryOperatingActivitiesBeforeGainsLossesFromFairValueAdjustments>
   <fsa:ProfitLossFromOrdinaryOperatingActivitiesBeforeGainsLossesFromFairValueAdjustments contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">7559000</fsa:ProfitLossFromOrdinaryOperatingActivitiesBeforeGainsLossesFromFairValueAdjustments>
   <fsa:OtherFinanceIncome contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">2141000</fsa:OtherFinanceIncome>
   <fsa:OtherFinanceIncome contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">3153000</fsa:OtherFinanceIncome>
   <fsa:OtherFinanceExpenses contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">214000</fsa:OtherFinanceExpenses>
   <fsa:OtherFinanceExpenses contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">186000</fsa:OtherFinanceExpenses>
   <fsa:ProfitLossFromOrdinaryActivitiesBeforeTax contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">6734000</fsa:ProfitLossFromOrdinaryActivitiesBeforeTax>
   <fsa:ProfitLossFromOrdinaryActivitiesBeforeTax contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">10526000</fsa:ProfitLossFromOrdinaryActivitiesBeforeTax>
   <fsa:TaxExpense contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">1566000</fsa:TaxExpense>
   <fsa:TaxExpense contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">2385000</fsa:TaxExpense>
   <fsa:ProfitLoss contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">5168000</fsa:ProfitLoss>
   <fsa:ProfitLoss contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">8141000</fsa:ProfitLoss>
   <fsa:FixturesFittingsToolsAndEquipment contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">905000</fsa:FixturesFittingsToolsAndEquipment>
   <fsa:FixturesFittingsToolsAndEquipment contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">156000</fsa:FixturesFittingsToolsAndEquipment>
   <fsa:LeaseholdImprovements contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">665000</fsa:LeaseholdImprovements>
   <fsa:LeaseholdImprovements contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">0</fsa:LeaseholdImprovements>
   <fsa:PropertyPlantAndEquipment contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">1570000</fsa:PropertyPlantAndEquipment>
   <fsa:PropertyPlantAndEquipment contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">156000</fsa:PropertyPlantAndEquipment>
   <fsa:DepositsLongtermInvestmentsAndReceivables contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">1375000</fsa:DepositsLongtermInvestmentsAndReceivables>
   <fsa:DepositsLongtermInvestmentsAndReceivables contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">546000</fsa:DepositsLongtermInvestmentsAndReceivables>
   <fsa:NoncurrentAssets contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">2945000</fsa:NoncurrentAssets>
   <fsa:NoncurrentAssets contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">702000</fsa:NoncurrentAssets>
   <fsa:ShorttermTradeReceivables contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">90240000</fsa:ShorttermTradeReceivables>
   <fsa:ShorttermTradeReceivables contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">108026000</fsa:ShorttermTradeReceivables>
   <fsa:ContractWorkInProgress contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">880000</fsa:ContractWorkInProgress>
   <fsa:ContractWorkInProgress contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">0</fsa:ContractWorkInProgress>
   <fsa:ShorttermReceivablesFromGroupEnterprises contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">0</fsa:ShorttermReceivablesFromGroupEnterprises>
   <fsa:ShorttermReceivablesFromGroupEnterprises contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">4109000</fsa:ShorttermReceivablesFromGroupEnterprises>
   <fsa:OtherShorttermReceivables contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">195000</fsa:OtherShorttermReceivables>
   <fsa:OtherShorttermReceivables contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">582000</fsa:OtherShorttermReceivables>
   <fsa:DeferredIncomeAssets contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">1713000</fsa:DeferredIncomeAssets>
   <fsa:DeferredIncomeAssets contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">3253000</fsa:DeferredIncomeAssets>
   <fsa:ShorttermReceivables contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">93028000</fsa:ShorttermReceivables>
   <fsa:ShorttermReceivables contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">115970000</fsa:ShorttermReceivables>
   <fsa:CashAndCashEquivalents contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">118563000</fsa:CashAndCashEquivalents>
   <fsa:CashAndCashEquivalents contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">111281000</fsa:CashAndCashEquivalents>
   <fsa:CurrentAssets contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">211591000</fsa:CurrentAssets>
   <fsa:CurrentAssets contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">227251000</fsa:CurrentAssets>
   <fsa:Assets contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">214536000</fsa:Assets>
   <fsa:Assets contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">227953000</fsa:Assets>
   <fsa:ContributedCapital contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">675000</fsa:ContributedCapital>
   <fsa:ContributedCapital contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">675000</fsa:ContributedCapital>
   <fsa:RetainedEarnings contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">49604000</fsa:RetainedEarnings>
   <fsa:RetainedEarnings contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">44436000</fsa:RetainedEarnings>
   <fsa:Equity contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">50279000</fsa:Equity>
   <fsa:Equity contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">45111000</fsa:Equity>
   <fsa:DeferredTaxLiabilitiesLongterm contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">2534000</fsa:DeferredTaxLiabilitiesLongterm>
   <fsa:DeferredTaxLiabilitiesLongterm contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">2296000</fsa:DeferredTaxLiabilitiesLongterm>
   <fsa:Provisions contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">2534000</fsa:Provisions>
   <fsa:Provisions contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">2296000</fsa:Provisions>
   <fsa:LongtermPrepaymentsReceivedFromCustomers contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">4151000</fsa:LongtermPrepaymentsReceivedFromCustomers>
   <fsa:LongtermPrepaymentsReceivedFromCustomers contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">4623000</fsa:LongtermPrepaymentsReceivedFromCustomers>
   <fsa:LongtermDeferredIncome contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">0</fsa:LongtermDeferredIncome>
   <fsa:LongtermDeferredIncome contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">208000</fsa:LongtermDeferredIncome>
   <fsa:LongtermLiabilitiesOtherThanProvisions contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">4151000</fsa:LongtermLiabilitiesOtherThanProvisions>
   <fsa:LongtermLiabilitiesOtherThanProvisions contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">4831000</fsa:LongtermLiabilitiesOtherThanProvisions>
   <fsa:ShorttermPrepaymentsReceivedFromCustomers contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">44714000</fsa:ShorttermPrepaymentsReceivedFromCustomers>
   <fsa:ShorttermPrepaymentsReceivedFromCustomers contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">47860000</fsa:ShorttermPrepaymentsReceivedFromCustomers>
   <fsa:ShorttermTradePayables contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">2453000</fsa:ShorttermTradePayables>
   <fsa:ShorttermTradePayables contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">3590000</fsa:ShorttermTradePayables>
   <fsa:ShorttermPayablesToGroupEnterprises contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">17836000</fsa:ShorttermPayablesToGroupEnterprises>
   <fsa:ShorttermPayablesToGroupEnterprises contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">12891000</fsa:ShorttermPayablesToGroupEnterprises>
   <fsa:ShorttermTaxPayables contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">400000</fsa:ShorttermTaxPayables>
   <fsa:ShorttermTaxPayables contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">1344000</fsa:ShorttermTaxPayables>
   <fsa:OtherPayablesIncludingTaxPayablesLiabilitiesOtherThanProvisionsShortterm contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">25237000</fsa:OtherPayablesIncludingTaxPayablesLiabilitiesOtherThanProvisionsShortterm>
   <fsa:OtherPayablesIncludingTaxPayablesLiabilitiesOtherThanProvisionsShortterm contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">29682000</fsa:OtherPayablesIncludingTaxPayablesLiabilitiesOtherThanProvisionsShortterm>
   <fsa:ShorttermDeferredIncome contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">66932000</fsa:ShorttermDeferredIncome>
   <fsa:ShorttermDeferredIncome contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">80348000</fsa:ShorttermDeferredIncome>
   <fsa:ShorttermLiabilitiesOtherThanProvisions contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">157572000</fsa:ShorttermLiabilitiesOtherThanProvisions>
   <fsa:ShorttermLiabilitiesOtherThanProvisions contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">175715000</fsa:ShorttermLiabilitiesOtherThanProvisions>
   <fsa:LiabilitiesOtherThanProvisions contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">161723000</fsa:LiabilitiesOtherThanProvisions>
   <fsa:LiabilitiesOtherThanProvisions contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">180546000</fsa:LiabilitiesOtherThanProvisions>
   <fsa:LiabilitiesAndEquity contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">214536000</fsa:LiabilitiesAndEquity>
   <fsa:LiabilitiesAndEquity contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">227953000</fsa:LiabilitiesAndEquity>
   <fsa:Equity contextRef="I5" decimals="-3" unitRef="U-iso4217-DKK">675000</fsa:Equity>
   <fsa:Equity contextRef="I6" decimals="-3" unitRef="U-iso4217-DKK">44436000</fsa:Equity>
   <fsa:ProfitLoss contextRef="D10" decimals="-3" unitRef="U-iso4217-DKK">0</fsa:ProfitLoss>
   <fsa:ProfitLoss contextRef="D11" decimals="-3" unitRef="U-iso4217-DKK">5168000</fsa:ProfitLoss>
   <fsa:Equity contextRef="I7" decimals="-3" unitRef="U-iso4217-DKK">675000</fsa:Equity>
   <fsa:Equity contextRef="I8" decimals="-3" unitRef="U-iso4217-DKK">49604000</fsa:Equity>
   <fsa:DisclosureOfAccountingPolicies contextRef="D0" xml:lang="en">The annual report of GARTNER DANMARK ApS for 2025 has been prepared in accordance with the provisions applying to reporting class C medium-sized entities under the Danish Financial Statements Act.The accounting policies used in the preparation of the financial statements are consistent with those of last year.</fsa:DisclosureOfAccountingPolicies>
   <fsa:ExplanationOfNotDisclosingCashFlowsStatements contextRef="D0" xml:lang="en">Omission of cash flow statementPursuant to section 86(4) of the Danish Financial Statements Act, no cash flow statement has been prepared. The Company's cash flows are included in the cash flow statement in the consolidated financial statements of Gartner Inc, 56 Top Gallant Road Stamford, CT 06902 USA.</fsa:ExplanationOfNotDisclosingCashFlowsStatements>
   <fsa:DescriptionOfMethodsOfForeignCurrencies contextRef="D0" xml:lang="en"> Foreign currency translation On initial recognition, transactions denominated in foreign currencies are translated at the exchange rates at the transaction date. Foreign exchange differences arising between the exchange rates at the transaction date and the date of payment are recognised in the income statement as financial income or financial expenses.  Receivables, payables and other monetary items denominated in foreign currencies are translated at the exchange rates at the balance sheet date. The difference between the exchange rates at the balance sheet date and the date at which the receivable or payable arose or was recognised in the latest financial statements is recognised in the income statement as financial income or financial expenses.</fsa:DescriptionOfMethodsOfForeignCurrencies>
   <fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfRevenue contextRef="D0" xml:lang="en"> Revenue Income from the sale of information technology and advisory-related services is recognised in revenue when delivery and transfer of risk to the buyer have taken place, and the income may be measured reliably and is expected to be received. Revenue is measured net of all types of discounts/rebated granted. Also, revenue is measured net of VAT and other indirect taxes charged on behalf of third parties.  Our revenue by significant source is accounted for as follows:- Insight revenue is mainly derived from subscription contracts for insights products. Related revenue is deferred and recognised ratably over the applicable contract term. Fees derived from assisting organisations in selecting the right business software for their needs are recognised when the leads are provided to vendors.-  Conference revenue is deferred and recognised upon the completion of the related conference or meeting.-  Consulting revenue is principally generated from fixed fee and time and materials engagements. Revenue from fixed fee contracts is recognised as we work to satisfy our performance obligations. Revenue from time and materials engagements is recognised as work is delivered and/or services are provided.Revenue related to contract optimisation engagements is contingent in nature and is only recognised upon satisfaction of all conditions related to their payment.The majority of insights contracts are billable upon signing. Insights contracts are generally non-cancelable and non-refundable, except for government contracts that may have cancellation or fiscal funding clauses.</fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfRevenue>
   <fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfCostOfSales contextRef="D0" xml:lang="en"> Cost of sales  Cost of sales comprises costs incurred to generate revenue for the year.</fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfCostOfSales>
   <fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfOtherOperatingIncome contextRef="D0" xml:lang="en"> Other operating income  Other operating income comprises items secondary to the activities of the Company, including gains on the disposal of intangible assets and property, plant and equipment as well as payroll refunds.</fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfOtherOperatingIncome>
   <fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfExternalExpenses contextRef="D0" xml:lang="en"> Other external costs  Other external costs include the year's costs relating to the entity's core activities, including costs relating to distribution, sales, advertising, administration, premises, bad debts, payments under operating leases, etc.</fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfExternalExpenses>
   <fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfEmployeeBenefitExpense contextRef="D0" xml:lang="en"> Staff costs  Staff costs comprise wages and salaries, including holiday allowance, pension and other social security costs.</fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfEmployeeBenefitExpense>
   <fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfFinanceIncomeAndExpenses contextRef="D0" xml:lang="en"> Financial income and expenses  Financial income and expenses comprise interest income and expense, financial costs and income regarding payables, receivables and transactions denominated in foreign currencies as well as surcharges and refunds under the on-account tax scheme, etc.</fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfFinanceIncomeAndExpenses>
   <fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfTaxExpenses contextRef="D0" xml:lang="en"> Tax on profit for the year  Tax for the year comprises current tax for the year and changes in deferred tax, including changes in tax rates. The tax expense relating to the profit/loss for the year is recognised in the income statement at the amount attributable to the profit/loss for the year and directly in equity at the amount attributable to entries directly in equity.</fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfTaxExpenses>
   <fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfPropertyPlantAndEquipment contextRef="D0" xml:lang="en">Property, plant and equipmentProperty, plant and equipment are measured at cost less accumulated depreciation and impairment losses. Cost includes the acquisition price and costs directly related to the acquisition until the time at which the asset is ready for use.Where individual components of an item of property, plant and equipment have different useful lives, they are accounted for as separate items, which are depreciated separately.Property, plant and equipment are depreciated on a straight-line basis over the expected useful life of each individual asset. The depreciable basis is cost.The expected useful lives of the assets are as follows:Fixtures and fittings, tools and equipment3-8 yearsLeasehold improve­ments5 yearsThe useful life and residual value are reassessed annually. Changes are treated as accounting estimates, and the effect on depreciation is recognised prospectively. Gains and losses on the disposal of property, plant and equipment are stated as the difference between the selling price less selling costs and the carrying amount at the date of disposal. Gains and losses are recognised in the income statement as other operating income or other operating costs, respectively.</fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfPropertyPlantAndEquipment>
   <fsa:DescriptionOfMethodsOfLeases contextRef="D0" xml:lang="en"> Leases  As of the balance sheet date, the Company solely operates with operating leases. Payments relating to operating leases and other leases are recognised in the income statement over the term of the lease. The Company's total obligation relating to operating leases and other leases is disclosed as contractual obligations, etc.</fsa:DescriptionOfMethodsOfLeases>
   <fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisForInvestmentsInSubsidiariesAndAssociates contextRef="D0" xml:lang="en"> Financial assets  Deposits are recognised at amortised cost.</fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisForInvestmentsInSubsidiariesAndAssociates>
   <fsa:DescriptionOfMethodsOfAmortisationOfNoncurrentAssets contextRef="D0" xml:lang="en"> Impairment of fixed assets The carrying amount of property, plant and equipment and financial assets is subject to an annual test for indications of impairment other than the decrease in value reflected by depreciation.  Impairment tests are conducted of individual assets or groups of assets when there is an indication that they may be impaired. Write-down is made to the recoverable amount if this is lower than the carrying amount.</fsa:DescriptionOfMethodsOfAmortisationOfNoncurrentAssets>
   <fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfReceivables contextRef="D0" xml:lang="en">ReceivablesReceivables are measured at amortised cost.Write-down is made for bad debt losses where there is an objective indication that a receivable has been impaired. If there is an objective indication that an individual receivable has been impaired, write-down is made on an individual basis.</fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfReceivables>
   <fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfContractWorkInProgress contextRef="D0" xml:lang="en"> Contract work in progress Contract work in progress are measured at the selling price of the work performed. The selling price is calculated on the basis of the stage of completion at the balance sheet date and the projected income from the relevant contract. The stage of completion is stated as the share of costs incurred in proportion to estimated total costs relating to the individual work. When the selling price of contract work in progress cannot be estimated reliably, the selling price is measured at the lower of costs incurred and net realisable value. The individual contract work is recognised in the balance sheet as receivables or payables, respectively.  Net assets comprise total work in progress where the selling price of the work performed exceeds progress billings. Net liabilities comprise total work in progress where progress billings exceed the selling price.  Costs arising from sales work and contracting are recognised in the income statement as incurred.</fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfContractWorkInProgress>
   <fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfDeferredIncomeAssets contextRef="D0" xml:lang="en"> Prepayments Prepayments comprise prepayment of costs incurred relating to subsequent financial years.  Prepayments received from customers include prepayments received for services not yet rendered, with recognition of revenue subsequent to the balance sheet date.</fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfDeferredIncomeAssets>
   <fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfTaxPayablesAndDeferredTax contextRef="D0" xml:lang="en"> Corporation tax and deferred tax Current tax payable and receivable is recognised in the balance sheet as tax computed on the taxable income for the year, adjusted for tax on the taxable income of prior years and for tax paid on account. Deferred tax is measured using the balance sheet liability method on all temporary differences between the carrying amount and the tax value of assets and liabilities measured on the planned use of the asset or settlement of the liability, respectively.  Deferred tax is measured in accordance with the tax rules and at the tax rates applicable at the balance sheet date when the deferred tax is expected to crystallise as current tax. Changes in deferred tax as a result of changes in tax rates are recognised in the income statement or equity, respectively.</fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfTaxPayablesAndDeferredTax>
   <fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfLiabilitiesOtherThanProvisions contextRef="D0" xml:lang="en">Liabilities other than provisionsFinancial liabilities are recognised at the date of borrowing at cost, corresponding to the proceeds received less transaction costs paid. In subsequent periods, the financial liabilities are measured at amortised cost, corresponding to the capitalised value using the effective interest rate. Accordingly, the difference between cost and the nominal value is recognised in the income statement over the term of the loan together with interest expenses.Other liabilities are measured at amortised cost.</fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfLiabilitiesOtherThanProvisions>
   <fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfDeferredIncomeLiabilities contextRef="D0" xml:lang="en"> Deferred income  Deferred income comprises income received for services where the services and the recognition of revenue have been initiated before the balance sheet date.</fsa:DescriptionOfMethodsOfRecognitionAndMeasurementBasisOfDeferredIncomeLiabilities>
   <fsa:WagesAndSalaries contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">116235000</fsa:WagesAndSalaries>
   <fsa:WagesAndSalaries contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">112078000</fsa:WagesAndSalaries>
   <fsa:PostemploymentBenefitExpense contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">8634000</fsa:PostemploymentBenefitExpense>
   <fsa:PostemploymentBenefitExpense contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">8662000</fsa:PostemploymentBenefitExpense>
   <fsa:SocialSecurityContributions contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">150000</fsa:SocialSecurityContributions>
   <fsa:SocialSecurityContributions contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">118000</fsa:SocialSecurityContributions>
   <fsa:AverageNumberOfEmployees contextRef="D0" decimals="0" unitRef="U-pure">51</fsa:AverageNumberOfEmployees>
   <fsa:AverageNumberOfEmployees contextRef="D6" decimals="0" unitRef="U-pure">52</fsa:AverageNumberOfEmployees>
   <fsa:DisclosureOfEmployeeBenefitsExpense contextRef="D0" xml:lang="en"> 
                                           In accordance with section 98b(3) of the Danish Financial Statements Act, the Company has not disclosed remuneration of Management as only one member of the Executive Board and Board of Directors has been remunerated in her capacity as member of the Executive Board and Board of Directors in 2024 and 2025. 
                                           All employees can sign up for Employee Stock Purchase Program (ESPP) vesting them with the right to purchase Gartner shares at a 5% discount compared to market price at the date of purchase. Employees can purchase shares for up to 10% of their monthly salary after tax. The scheme is limited to a maximum amount that is adjusted quarterly. In addition, Gartner Inc. grants stock-based compensation awards (shares) as an incentive for senior leaders to contribute to Gartner Inc.’s long-term success. The shares are granted and settled by Gartner Inc. as Restricted Stock Units. The Restricted Stock Units are vested within 4 years. In 2025, an expense of DKK 2,340 thousand (2024: an expense of DKK 1,692 thousand) was recognised in the income statement related to the Employee Stock Purchase Program. A total number of 855 Restricted Stock Units were granted during 2025 to employees with a fair value of USD 534.45 per RSU. As of 31 December 2025, a total of 1,900 RSU’s are open for vesting during the next years.</fsa:DisclosureOfEmployeeBenefitsExpense>
   <fsa:InterestIncomeFromGroupEnterprises contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">0</fsa:InterestIncomeFromGroupEnterprises>
   <fsa:InterestIncomeFromGroupEnterprises contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">-4000</fsa:InterestIncomeFromGroupEnterprises>
   <fsa:OtherInterestIncome contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">-2141000</fsa:OtherInterestIncome>
   <fsa:OtherInterestIncome contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">-3149000</fsa:OtherInterestIncome>
   <fsa:InterestExpenseAssignedToGroupEnterprises contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">28000</fsa:InterestExpenseAssignedToGroupEnterprises>
   <fsa:InterestExpenseAssignedToGroupEnterprises contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">0</fsa:InterestExpenseAssignedToGroupEnterprises>
   <fsa:OtherInterestExpenses contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">186000</fsa:OtherInterestExpenses>
   <fsa:OtherInterestExpenses contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">186000</fsa:OtherInterestExpenses>
   <fsa:TransferredToFromRetainedEarnings contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">5168000</fsa:TransferredToFromRetainedEarnings>
   <fsa:TransferredToFromRetainedEarnings contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">8141000</fsa:TransferredToFromRetainedEarnings>
   <fsa:PropertyPlantAndEquipmentGross contextRef="I9" decimals="-3" unitRef="U-iso4217-DKK">3475000</fsa:PropertyPlantAndEquipmentGross>
   <fsa:PropertyPlantAndEquipmentGross contextRef="I10" decimals="-3" unitRef="U-iso4217-DKK">0</fsa:PropertyPlantAndEquipmentGross>
   <fsa:AdditionsToPropertyPlantAndEquipment contextRef="D12" decimals="-3" unitRef="U-iso4217-DKK">868000</fsa:AdditionsToPropertyPlantAndEquipment>
   <fsa:AdditionsToPropertyPlantAndEquipment contextRef="D13" decimals="-3" unitRef="U-iso4217-DKK">712000</fsa:AdditionsToPropertyPlantAndEquipment>
   <fsa:DisposalsOfPropertyPlantAndEquipment contextRef="D12" decimals="-3" unitRef="U-iso4217-DKK">-135000</fsa:DisposalsOfPropertyPlantAndEquipment>
   <fsa:DisposalsOfPropertyPlantAndEquipment contextRef="D13" decimals="-3" unitRef="U-iso4217-DKK">0</fsa:DisposalsOfPropertyPlantAndEquipment>
   <fsa:PropertyPlantAndEquipmentGross contextRef="I11" decimals="-3" unitRef="U-iso4217-DKK">4208000</fsa:PropertyPlantAndEquipmentGross>
   <fsa:PropertyPlantAndEquipmentGross contextRef="I12" decimals="-3" unitRef="U-iso4217-DKK">712000</fsa:PropertyPlantAndEquipmentGross>
   <fsa:AccumulatedImpairmentLossesAndDepreciationOfPropertyPlantAndEquipment contextRef="I9" decimals="-3" unitRef="U-iso4217-DKK">-3319000</fsa:AccumulatedImpairmentLossesAndDepreciationOfPropertyPlantAndEquipment>
   <fsa:AccumulatedImpairmentLossesAndDepreciationOfPropertyPlantAndEquipment contextRef="I10" decimals="-3" unitRef="U-iso4217-DKK">0</fsa:AccumulatedImpairmentLossesAndDepreciationOfPropertyPlantAndEquipment>
   <fsa:DepreciationOfPropertyPlantAndEquipment contextRef="D12" decimals="-3" unitRef="U-iso4217-DKK">-118000</fsa:DepreciationOfPropertyPlantAndEquipment>
   <fsa:DepreciationOfPropertyPlantAndEquipment contextRef="D13" decimals="-3" unitRef="U-iso4217-DKK">-47000</fsa:DepreciationOfPropertyPlantAndEquipment>
   <fsa:ReversalsOfImpairmentLossesOfPropertyPlantAndEquipmentFromPreviousPeriods contextRef="D12" decimals="-3" unitRef="U-iso4217-DKK">134000</fsa:ReversalsOfImpairmentLossesOfPropertyPlantAndEquipmentFromPreviousPeriods>
   <fsa:ReversalsOfImpairmentLossesOfPropertyPlantAndEquipmentFromPreviousPeriods contextRef="D13" decimals="-3" unitRef="U-iso4217-DKK">0</fsa:ReversalsOfImpairmentLossesOfPropertyPlantAndEquipmentFromPreviousPeriods>
   <fsa:AccumulatedImpairmentLossesAndDepreciationOfPropertyPlantAndEquipment contextRef="I11" decimals="-3" unitRef="U-iso4217-DKK">-3303000</fsa:AccumulatedImpairmentLossesAndDepreciationOfPropertyPlantAndEquipment>
   <fsa:AccumulatedImpairmentLossesAndDepreciationOfPropertyPlantAndEquipment contextRef="I12" decimals="-3" unitRef="U-iso4217-DKK">-47000</fsa:AccumulatedImpairmentLossesAndDepreciationOfPropertyPlantAndEquipment>
   <fsa:PropertyPlantAndEquipment contextRef="I11" decimals="-3" unitRef="U-iso4217-DKK">905000</fsa:PropertyPlantAndEquipment>
   <fsa:PropertyPlantAndEquipment contextRef="I12" decimals="-3" unitRef="U-iso4217-DKK">665000</fsa:PropertyPlantAndEquipment>
   <fsa:InvestmentsGross contextRef="I13" decimals="-3" unitRef="U-iso4217-DKK">546000</fsa:InvestmentsGross>
   <fsa:AdditionsToInvestments contextRef="D14" decimals="-3" unitRef="U-iso4217-DKK">829000</fsa:AdditionsToInvestments>
   <fsa:InvestmentsGross contextRef="I14" decimals="-3" unitRef="U-iso4217-DKK">1375000</fsa:InvestmentsGross>
   <fsa:LongtermInvestmentsAndReceivables contextRef="I14" decimals="-3" unitRef="U-iso4217-DKK">1375000</fsa:LongtermInvestmentsAndReceivables>
   <fsa:SalesValueOfWorkPerformedContractWorkInProgress contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">1320000</fsa:SalesValueOfWorkPerformedContractWorkInProgress>
   <fsa:SalesValueOfWorkPerformedContractWorkInProgress contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">0</fsa:SalesValueOfWorkPerformedContractWorkInProgress>
   <fsa:AdvanceInvoicingContractWorkInProgress contextRef="D0" decimals="-3" unitRef="U-iso4217-DKK">-440000</fsa:AdvanceInvoicingContractWorkInProgress>
   <fsa:AdvanceInvoicingContractWorkInProgress contextRef="D6" decimals="-3" unitRef="U-iso4217-DKK">0</fsa:AdvanceInvoicingContractWorkInProgress>
   <fsa:ContractWorkInProgress contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">880000</fsa:ContractWorkInProgress>
   <fsa:ContractWorkInProgress contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">0</fsa:ContractWorkInProgress>
   <fsa:ExplanationOfPrepayments contextRef="D0" xml:lang="en"> 
                                           Prepayments comprise of prepaid commission of DKK 1,029 thousand as of 31 December 2025 (31 December 2024: DKK 2,693 thousand) and other prepaid costs of DKK 684 thousand (31 December 2024: DKK 560 thousand).</fsa:ExplanationOfPrepayments>
   <fsa:DisclosureOfCashAndCashEquivalents contextRef="D0" xml:lang="en"> 
                                           The Company has deposited DKK 99,000 thousand in restricted cash with its banking institution. The restricted cash carries a fixed interest rate and has maturity within one month from the balance sheet date. The funds are classified as restricted cash and are not available for use until the respective maturity date.</fsa:DisclosureOfCashAndCashEquivalents>
   <fsa:ProvisionsForDeferredTax contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">2296000</fsa:ProvisionsForDeferredTax>
   <fsa:ProvisionsForDeferredTax contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">2475000</fsa:ProvisionsForDeferredTax>
   <fsa:DeferredTaxRecognisedInIncomeStatement contextRef="I0" decimals="-3" unitRef="U-iso4217-DKK">238000</fsa:DeferredTaxRecognisedInIncomeStatement>
   <fsa:DeferredTaxRecognisedInIncomeStatement contextRef="I1" decimals="-3" unitRef="U-iso4217-DKK">-179000</fsa:DeferredTaxRecognisedInIncomeStatement>
   <fsa:DisclosureOfDeferredIncome contextRef="D0" xml:lang="en"> 
                                           Deferred income comprises income received for services where the services and the recognition of revenue have been initiated before the balance sheet date.</fsa:DisclosureOfDeferredIncome>
   <fsa:DisclosureOfLiabilitiesUnderLeases contextRef="D0">
                        Other commitments, including lease obligations      Rent and lease liabilities include a rent obligation totaling DKK 4,658 thousand. (31 December 2024: DKK 530 thousand) regarding non-cancellable rent agreements with a remaining term of 39 months.  The Company has extended service agreements totaling DKK 3,738 thousand with a remaining term of 39 months.  </fsa:DisclosureOfLiabilitiesUnderLeases>
   <fsa:InformationOnRelatedEntities contextRef="D0">
                        Consolidated financial statements  
                                                                  Gartner Danmark ApS is part of the consolidated financial statements of Gartner, Inc., 56 Top Gallant Road Stamford, CT 06902 USA, which is the smallest and largest group, in which the Company is included as a subsidiary.
                        Related party transactions DKK'0002025 
                          
                                           Purchase of services from group entities
                        95,900 
                          
                                           Sales of services to group entities
                        32,796
                         
                                             In accordance with section 98b(3) of the Danish Financial Statements Act, the Company has not disclosed remuneration of Management as only one member of the Executive Board and Board of Directors was remunerated in the capacity as member of the Executive Board and Board of Directors in 2024 and 2025.  
                         
                                             Payables to and receivables from group entities are disclosed in the balance sheet.  
                         
                                             Interest income and expenses from/to group entities are disclosed in note 3 and 4 to the financial statements.  </fsa:InformationOnRelatedEntities>
</xbrli:xbrl>
