Making changes to tax return

Changing Your Tax Return

Income Tax Act S. 142(4.2)

If you have 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 2016, you can request a change for the 2006 or later taxation years.

Requesting a Change Online

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. In order to request the change, it is helpful to know the line number from your tax return which you wish to change.

You can also use the online request if you forgot to apply for the GST/HST tax credit when you filed your tax return.

Requesting a Change by Mail

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.

CRA Resources

How to change your return.