Calculating Source Deductions of Income Tax
In general, if you are not required to use either a fixed rate or the method applicable to gratuities to calculate source deductions on the remuneration you pay, you can use one of the following tools:
- the WinRAS – Calculation of Source Deductions and Employer Contributions application;
- the source deduction table for Québec income tax; or
- the formulas provided in guide TP-1015.F-V, Formulas to Calculate Source Deductions and Contributions.
For information about how to calculate source deductions on various types of remuneration, see Remuneration Subject to Source Deductions of Québec Income Tax.
The WinRAS application can be used to calculate a source deduction of Québec income tax for a single pay period. However, it does not produce cumulative data for successive pay periods.
When calculating source deductions, you must take into account certain amounts that will affect the amount of Québec income tax to be withheld.