Product Description

Quebec Payroll Tax Library

QPTL is a library of Québec payroll withholding tax deduction calculations for payroll application software developers. QPTL enables payroll software developers to easily, quickly, and seamlessly incorporate a full set of Revenu Québec payroll deduction calculations into their software by utilizing the QPTL SDK and API.  QPTL includes calculation methods for Québec Pension Plan (QPP), Québec Parental Insurance Plan (QPIP), and province of Québec income tax withholding.

(Looking for our Canadian Payroll Tax Library (CPTL)?  Click here.) 

Payroll software developers can reduce their total costs of development and maintenance, and significantly reduce development time, by employing QPTL in their applications.  QPTL is easy to implement in any .NET or Java application, with full documentation and sample programs provided for using QPTL in VC++, VC#, VB, ASP.NET & Java applications.  A free trial is available for qualified developers by completing our online QPTL Trial License application form.

New!  QPTL REST API now available!

QPTL REST API is easy to implement in web-based applications using a standard REST interface.  Download and import our Swagger specification file and start sending payroll deduction calculation requests from your application within minutes.

QPTL is also available as a software library (Windows .NET DLL or Java) for developers needing to package their payroll software for distribution as a locally installed executable.

QPTL is updated whenever Revenu Québec changes/updates their specifications and requirements for payroll withholding calculations - usually on January 1 of each year. Our quality assurance process ensures that all calculations are tested extensively and results match exactly to all Revenu Québec test cases. As a payroll software provider, you can be assured that your Québec tax deduction calculations are up-to-date and accurate with QPTL.

Payroll software vendors typically face the challenge of distributing updates to customers on a timely basis, in advance of implementation dates for new Revenu Québec rates and changes in calculation methods. We distribute QPTL updates to our customers within 7-10 days of any Revenu Québec publication of changes to required payroll withholding rules, which are usually received 30 days in advance of the effective date for those changes, allowing our customers ample time to integrate the updated QPTL and perform their own testing and quality assurance on their payroll application before deploying updates to end-users.


  • Performs all Québec payroll deduction calculations, including employee QPP, QPIP and Québec provincial income tax withholdings, and employer contributions to QPP, QPIP, and Québec Health Services Fund contributions.
  • Handles all pay period types, including daily, weekly, bi-weekly, semi-monthly, and monthly.
  • Handles all types of earnings subject to Quebec payroll tax withholding, including Salary, Wages, Vacation Pay, Pension Income, Bonuses, Retroactive Pay, & Commission payments.
  • Available as a Microsoft Dynamic Link Library (DLL) or a Linux shared library (.so).
  • QPTL can be linked statically at compile time using the provided QPTL.LIB file, or alternatively, QPTL can be loaded dynamically (at load-time or run-time) - e.g. by using the Microsoft API functions LoadLibrary, LoadLibraryEx, FreeLibrary and GetProcAddress with the Microsoft Dynamic Link Library (DLL) version of QPTL.
  • 'Wrapper' interfaces available for Visual BasicJava.Net, PHPASP, and JSP applications.
  • Cost-effective unlimited end-user license terms allow you to re-distribute QPTL with your application.
  • Reduce annual costs of developing and maintaining up-to-date Québec payroll deduction calculations code.
  • Our extensive testing and results verification process ensures the accuracy of payroll deduction calculations returned by the QPTL module. QPTL calculation results are verified against all Revenu Québec examples and test case results by a Canadian Chartered Accountant.