If you’ve made an error on your tax return, don’t let it ruin your day! It’s a common occurrence, but the good news is that rectifying it after filing is quite simple. So take a breath—here’s how to make the fix and the steps you need to know to refile your taxes

Key Takeaways
  1. If you make a mistake you can still change your tax returns after you file your taxes.
  2. Wait to receive a Notice of Assessment first before making changes.
  3. You can amend your returns dating back 10 years.

What happens if I make a mistake on my tax return?

If you entered something incorrectly on your tax return, you simply correct it with the Canada Revenue Agency (CRA). Mistakes happen, and the CRA recognizes this.

Things like missing a receipt, overlooking a deduction, the late arrival of a tax slip, or entering a number incorrectly can all be reasons to change your tax return. 

The CRA helps you amend tax returns with relative ease. You simply fill out Form T1-ADJ—either electronically or a paper copy—which is specifically designed for amending your tax return. Think of it as fine-tuning your initial submission.

How do I amend my tax return with the CRA?

You can fill out the T1-ADJ Form via ReFILE, through your CRA My Account, or by sending it via postal mail.

Filling out the form is quite straightforward. You’ll fill in your social insurance number, the tax year you’re making changes to, your name, and address. Then you simply list the specific line numbers on your tax return that you need to report changes for.

Let’s look at the example provided in the instruction area of the form.

Mary reported $28,600 employment income on line 10100 of her 2019 tax return. She also listed $500 in union dues on line 21200. Later she received a T4 slip showing another $200 of income and $20 union dues. So when filling out the adjustment request form, she would enter those changes. See below:

Line number from return or schedule

Name of line from return or schedule

Previous amount


Amount of change

Revised amount


Employment income






Union dues





Exactly how do I refile my taxes in Canada?

Once you realize you’ve made an error, you’ll probably want to refile your taxes or file an amendment ASAP. But as a general rule, wait until you receive your Notice of Assessment (NOA) from the CRA.

You can refile up to 4 years or file an amendment for up to 10 years.

Once you’ve reviewed your NOA, there are three different ways to amend or refile your taxes.


Using ReFILE is the fastest, easiest, and most cost-effective way to make changes to your previously filed tax return. Simply submit your adjustments using the same certified NETFILE software you used when you filed your tax return.

Currently, ReFILE services are not available for residents of Quebec.

2. CRA My Account

Sign in to your CRA My Account and click “Change my return.” After selecting the tax year and line that needs to be changed, you can input the correct information to submit your changes.

Once you submit an adjustment request online, you can’t submit another one until the first one has been finalized. You’re allowed to make multiple adjustments on the same request, so try to have all your information ready.

Restrictions: You can only use CRA My Account to submit certain types of changes to your tax return. For more details, visit the conditions and exclusions for using “Change my return” on the CRA website. 

3. Mail

To make changes to your tax return by mail, you’ll have to complete a paper copy of the T1 Adjustment Request form and send it with all supporting documents for the change to your local tax centre

If you’re a resident of Québec, please visit the Revenu Québec website for detailed instructions on how to amend a tax return. 

Regardless of how you choose to file your current or amended tax return, remember to save all of your paperwork. You can adjust multiple tax returns dating as far back as 10 years, so make sure you hang on to old receipts, tax slips, and other documentation. When you have these, it makes refiling and amending possible, faster, and easier.

What happens after I submit my changes on my tax return?

Once your review is complete, you’ll receive one of the following from the CRA:

  • A Notice of Reassessment, which looks almost exactly like an NOA except with the amended parts highlighted. It’s important to review this notice as soon as possible so that if you owe money, you can pay it off without unnecessary interest or penalties.
  • A letter explaining why the changes you asked for weren’t applied.

Processing timelines differ depending on how you submit your changes and how complex your situation is.

Online (ReFILE & CRA My Account)

2 weeks


8 weeks

If you don’t hear from the CRA right away, try not to lose any sleep. While tax season equals busy season, requests like yours are a priority, and the CRA is working on your behalf. Believe it or not, they want this thing resolved as much as you do.

When are tax returns due in Canada?

Tax returns are due by April 30, 2024, at the latest. This tax due date is for individuals, however. If you’re self-employed, the final date to file your current taxes is June 17, 2024.

If you’d like to file faster, NETFILE opens on February 19, 2024.

Where do I send my tax return in Canada?

The easiest way to send your tax return to the CRA is through NETFILE. If you prefer to send it via mail, however, you’ll find the address for your local tax centre online.

File with confidence

Get advice and answers as you go and a final tax expert review before you file.