Filing Your Return -> Adjusting Your Tax Return
Changing / Amending Your Tax Return
Income Tax Act S. 142(4.2)
If you've filed your return and then determine that you need to make a change, either because you have received another T-slip, or because you didn't claim an expense and later learned it was deductible, you can request an adjustment to your tax return.
The time limit for filing most adjustments to your tax returns by mail is ten (10) years. For a late or amended pension splitting election the time limit is three (3) years - see our Pension Splitting article.
You can request the change for your most recent return, or your returns for the previous 9 tax years, either online or by mail. In 2018, you can request a change for the 2008 or later taxation years.
If you used a tax professional to file your tax return, they can also file an amendment for you.
Requesting a change online is very simple, and is done by logging into your account at the Canada Revenue Agency (CRA) My Account page. You can request changes to more than one tax year in one session, but each tax year is done separately.
There are some changes you cannot make using My Account. See the link at bottom to the CRA Change my return information for exclusions.
When you log into My Account, if it shows a link to your most recent assessment on the Overview page, you can select the Change my return icon in order to make a change. For a prior year, click on
If you are trying to correct a prior return because you didn't enter all your RRSP contributions, see our article RRSP Contribution Not Recorded Last Year.
You can also use the online request if you forgot to apply for the GST/HST tax credit when you filed your tax return.
If you filed your return using tax preparation software, you can use the same software to change your return, using CRA's ReFILE service (see link at bottom). CRA's Certified tax software for the NETFILE program indicates what level of ReFILE service each software product provides. ReFile can be used to file amendments for the immediately past tax year and 3 previous tax years - the same years that can be filed via NetFile or EFile.
Some things cannot be changed using ReFILE - see ReFILE exclusions on the CRA website.
To do this in your tax software, instead of Open an existing return, you probably have to choose Change a filed return.
You can obtain a form T1-Adj, T1 Adjustment Request from the CRA web site, complete it and mail it in, along with documents supporting your change request.
How Long Will My Adjustment Take?
The processing time is usually within 2 weeks for an online request, and within 8 weeks for a mailed request. CRA will either send you a reassessment notice indicating changes that were made to your return, or will explain in a letter why the requested changes were not made.
Canada Revenue Agency (CRA) Resources
Revised: June 17, 2021
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