Whether it’s a T slip that arrived late or a forgotten RRSP contribution receipt, sometimes your tax return ends up missing a few details. If you’ve already filed your return, correcting mistakes may be easier than you think. Here’s how to change your tax return after you’ve filed.

Same Return – New Info

The Canada Revenue Agency will only accept one return per tax year. Once you’ve filed your return (mistakes and all), you can’t file a new one. But you can correct the original by way of an adjustment.

You must wait until you have received your Notice of Assessment before submitting any adjustment requests. This is important for a couple of reasons. First, an early adjustment request may lead to unnecessary delays in processing time for both the original return and the adjustment. Secondly, CRA may adjust your original return for you. For example, if you’ve forgotten to include unused tuition to your return, CRA has those figures and may add the amounts to your return directly.

CRA has two ways for you to file an adjustment request – online or by mail. Online submissions are usually much quicker. The average processing time for CRA My Account adjustments is about two weeks. Adjustments filed by mail can take up to ten weeks to process.

Online Changes

If you’re a CRA My Account holder, changes to your return can be submitted online via the portal. After signing into your account, click the “Change return” option from the left side. You’ll choose the tax year you want to adjust and enter line numbers and figures to correct or add information. Online adjustments process in about two weeks. Once your adjustment request has been processed, you’ll receive a Notice of Reassessment which outlines approved changes. If your adjustment request is not approved, you’ll receive a letter of explanation from CRA.

As soon as you submit an adjustment request online, you can’t submit another until the first one has been finalized. If you have more than one adjustment to make, try to have all of your information ready at once and do it all in one shot. You are allowed to make multiple adjustments all on one request.

Some changes can’t be done online. Check out CRA’s How to change your return webpage for details.

Changes by Mail

If you prefer to submit your adjustment request by paper, fill out a Form T1ADJ – T1 Adjustment Request and mail to your local tax centre. Along with the completed form, you’ll also need to include any supporting documents (receipts, slips, etc.).

Going Back in Time

If you’ve just realized you could have been claiming your child’s daycare expenses or soccer registration fees for the past few years, it’s not too late. CRA allows taxpayers to adjust returns going back 10 years. So gather those old receipts and claim the expenses before the ten-year deadline.

References & Resources