Product Description

Canadian Payroll Tax Library

Canadian Payroll Tax Library (CPTL) is a library of Canadian payroll tax calculations available for licensing to payroll application software developers. CPTL allows payroll software developers to easily, quickly, and seamlessly incorporate a full set of Canada Revenue Agency (CRA) payroll deduction calculations into their software by including or compiling the CPTL Library or making REST calls from a web-based payroll application.  CPTL includes calculation methods for Canada/Quebec Pension Plan (CPP/QPP) contributions, Employment Insurance (EI) premiums, and federal and provincial/territorial (excluding Quebec) income tax withholdings.

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

Payroll software developers can reduce their total costs of development and maintenance, and significantly reduce development time, by employing CPTL in their applications.  CPTL is easy to implement in any .NET or Java application, with full documentation and sample programs provided for using CPTL in VC++, VC#, VB, ASP.NET & Java applications.  

New!  CPTL REST API now available!

CPTL 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.

CPTL is also available as a developer software library (Windows .NET DLL or Java) for developers needing to package their payroll software for distribution as a locally installed executable. A free trial is available for qualified developers by completing our online CPTL Developer Library Trial License application form.

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

Payroll software vendors typically face the challenge of distributing updates to customers on a timely basis, in advance of implementation dates for new CRA rates and changes in calculation methods. We distribute CPTL updates to our library customers within 7-10 days of any CRA publication of changes to required payroll withholding rules, which are usually received 30-45 days in advance of the effective date for those changes, allowing our customers ample time to integrate the updated CPTL and perform their own testing and quality assurance on their payroll application before deploying updates to end-users.  Our CPTL REST API service is also updated automatically by us within 7-10 days of CRA publication of changes, so as a CPTL REST API subscriber, you don't need to change anything in your payroll software - CPTL REST API will provide you with updated calculation results in response to your payroll software's existing REST API requests.


  • Calculate all required Canadian federal and provincial or territorial (excluding Quebec) payroll withholding amounts, including employee CPP/QPP, EI, and income tax withholdings, and employer contributions to CPP/QPP, EI, and Ontario Health Services premiums.
  • Calculations for all pay period types, including daily, weekly, bi-weekly, semi-monthly, and monthly.
  • Calculations for all types of earnings subject to Canadian payroll tax withholding, including Salary, Wages, Vacation Pay, Pension Income, Bonuses, Retroactive Pay, & Commission payments.
  • CPTL REST API calls can be implemented quickly and easily into any web-based payroll application.
  • Available as a Microsoft Dynamic Link Library (DLL), Linux shared library (.so) or Java .jar package.
  • For C++ developers, CPTL can be linked statically at compile time using the provided .LIB files, or alternatively, CPTL 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 CPTL.
  • Cost-effective unlimited end-user license terms allow you to re-distribute CPTL library with your application code to all your end-users.
  • Reduce annual costs of developing and maintaining up-to-date Canadian payroll deduction calculations code.
  • Our extensive testing and results verification process ensures the accuracy of payroll deduction calculations returned by the CPTL module. CPTL calculation results are verified against all CRA-provided test case results by a Canadian Chartered Professional Accountant.