What is a Social Insurance Number (SIN)?

Your social insurance number (SIN) is a unique 9-digit number that lets you work in Canada and access government programs and benefits (like the Canada Pension Plan, Employment Insurance program, or Canada Student Loans). Your SIN is formatted in groups of three digits (such as 234-567-890) and can be found on:

  • Your confirmation of SIN letter or valid SIN card issued by Service Canada
  • The first page of your previous year’s Canadian tax return or
  • Your notice of assessment or reassessment from the Canada Revenue Agency (CRA) or Revenu Québec

Remember, to successfully file your taxes, you’ll need to enter your SIN on your tax return – it's your main identifier with the CRA (and Revenu Québec, if applicable).

What if my spouse doesn’t have a SIN number?

Your spouse only requires a SIN number if you are

  • Preparing a coupled return 
  • Splitting pension income with your spouse
  • Living in Québec and your spouse is a resident 

If any of these situations apply to you, and your spouse does not have a SIN number, please check out our website to find one of our retail locations near you. Our Tax Experts would be happy to help you with your return!


Where can I learn more?