When payroll deductions are calculated at each of your jobs, your salary or wages for the payroll period are annualized to determine the income tax rate. As a result, you are paying income tax at a rate that assumes you will be earning the same amount per pay period for a year.
If you are working at 2 or more jobs in the same month, and this continues throughout the year, you may owe income taxes at the end of the year. Your payroll tax deductions are determined by the TD1 forms (both federal and provincial/territorial) that you fill out for the employer when you are hired.
Individuals who have more than one employer at the same time cannot claim deductions on more than one TD1 form. If total income from all employers and payers will be more
than the deductions claimed on the TD1 already filed with an employer, then the box "More than one employer or payer at the same time" on the back of the TD1 form should be ticked, and "0" should be entered on line 13 on page 1 of the TD1. Lines 2 to 12 should not be completed.
Use the Canadian Tax Calculator for your province or territory to estimate the tax that you will owe at the end of the year.
For more information on federal and provincial/territorial TD1 forms, see our TD1 Forms article.
Tax Tip: It is mandatory to fill out a TD1 form for each employer. Make sure the form is completed correctly.
Revised: March 10, 2015