How to Find and Correct Errors on Your CRA Notice of Assessment

Your CRA Notice of Assessment (NOA) is one of the most important documents you'll receive after filing your taxes. It confirms your tax filing details, shows your tax owing or refund, and lists your RRSP contribution room. If you spot an error on your NOA, the good news is that the CRA makes it straightforward to request a correction. This guide walks you through identifying mistakes, understanding what can be corrected, and submitting a correction request. Your NOA is the CRA's official response to your tax return. It arrives by mail (typically within 6-8 weeks of filing) or you can view it in CRA My Account right away. The NOA shows: Your total income and tax paid Tax credits you claimed Your refund amount or balance owing Your RRSP deduction limit for next year Your TFSA contribution room Any adjustments the CRA made to your return While the CRA processes millions of returns, mistakes do happen.

Frequently Asked Questions

How long do I have to correct an error on my Notice of Assessment?

There is no strict deadline to request a correction, but the sooner you catch and report an error, the better. The CRA can assess or reassess your return within six years, so don't delay if you spot something wrong.

Will correcting my Notice of Assessment affect my future tax returns?

Yes, corrections to your income, deductions, or credits will carry forward to future years. For example, correcting your RRSP contribution room now ensures next year's room is calculated correctly.

Can I request a correction if I disagree with the CRA's decision to disallow a deduction?

If the CRA disallows a deduction, a simple adjustment request won't overturn that decision. You would need to file a Notice of Objection within 90 days of your NOA to formally dispute it.

What documents do I need to send with a T1-ADJ form?

Include any receipts, pay stubs, bank statements, or other proof that supports your correction request. The more documentation you provide, the faster the CRA can process your request.

Can the CRA correct errors they made on my NOA automatically?

Sometimes yes, especially for obvious calculation mistakes. However, it's best to contact them directly rather than wait, since they may not catch all errors on their own.

Steps

  1. Review your Notice of Assessment carefully: When you receive your NOA by mail or see it in CRA My Account, read through every line. Compare income amounts to your T4s and T5s, verify that credits you claimed are listed, and check that your RRSP and TFSA contribution room amounts look correct based on your records.
  2. Gather supporting documentation: Collect any receipts, pay stubs, investment statements, or other proof that backs up your correction request. Organize them clearly so the CRA can quickly verify your claim if needed.
  3. Decide whether to use CRA My Account or submit a form: For simple corrections, log into CRA My Account and use the Service requests or Adjust my return feature. For complex issues or if you prefer mailing a form, download the T1-ADJ form from canada.ca.
  4. Submit your correction request with details: If using CRA My Account, follow the on-screen prompts and explain what's incorrect. If mailing a T1-ADJ, write a clear cover letter explaining the error, which line it appears on, and why you believe it's wrong. Include page numbers if referring to attached documents.
  5. Wait for the CRA response: Check CRA My Account regularly for updates on your request status. Simple corrections typically take 4-8 weeks; more complex ones may take longer. The CRA will mail you a letter if they agree or disagree with your correction.