Form T1-ADJ is the CRA's paper request to change an individual income tax return you've already filed and had assessed. Most changes are faster online through Change my Return in your CRA account or ReFILE in tax software, so T1-ADJ is mainly for returns those services can't handle, such as years before 2016, bankruptcy returns or some non-resident returns.
These rules come from the CRA's T1-ADJ form page, the current T1-ADJ E (23) form and the CRA's page on changing a tax return, as of October 2026.
Wait for your notice of assessment first
You can't ask for a change until you've received your notice of assessment for that year. And if you've already sent a change request, wait for the CRA's answer before sending another one for the same return. Two requests in flight for one year is a common cause of delays.
Online or T1-ADJ: which one to use
| Route | Processing time the CRA quotes | Can't be used for |
|---|---|---|
| Change my Return (CRA account) | 2 weeks | 2015 or earlier, bankruptcy returns, optional deceased returns, wrong province returns, some non-resident returns |
| ReFILE (certified tax software) | 2 weeks | Years before 2021, bankruptcy and deceased optional returns, non-resident and emigrant returns, returns needing Form T2203 |
| T1-ADJ by mail | 19 weeks | Works for the cases above, with limits on very old years |
The CRA's T1-ADJ page puts it bluntly: the webform or paper form may take 19 weeks because of high volumes. If any online route works for your situation, use it.
What you can and can't change
- You can report income you missed, such as a T4 slip or tips.
- You can claim a deduction, credit or expense you forgot, such as child care or medical costs.
- You can add a missing slip, such as an RRSP contribution receipt.
- You can't use an adjustment to apply for benefits or credits, make or revise an election, or move a refund to another CRA account.
- You can't update your address, direct deposit, marital status or name this way. Those are separate updates.
How to fill in T1-ADJ
- Area A: your SIN, name, address and the tax year. Use a separate form for each year you're changing.
- Area B: only if someone else is making the request for you. They need Form AUT-01 on file with Option 2 access, which allows changes to your account.
- Area C: for each change, give the line number and name, the previous amount, the plus or minus amount of change and the revised amount. Don't send a recalculation of your tax: the CRA does that.
- Area D: sign and date it, or have your authorized representative sign.
- Attach supporting documents and mail it, separately from your current-year return, to the tax centre that serves your area.
Small details that cause rejections
- For each change, pick the right plus or minus sign. For a loss, such as a self-employed business loss, choose minus.
- The CRA only accepts a change of address from you or your legal representative, meaning an executor, administrator, someone with power of attorney or a guardian.
- If a family member or friend changes your return online, they must be an authorized representative with at least level 2 access.
- ReFILE isn't available from 3 am to 6 am ET each day, or from February 2 to 23, 2026 while software is updated for the tax year.
The documentation rule that slows people down
If you change a line where you'd already claimed an amount and you never sent receipts for it, you must now send documents for the entire revised amount, not only the extra. The CRA's own example on the form: Mary reported employment income of $28,600 and union dues of $500, then got a late T4 showing $200 more income and $20 more in union dues. Her request shows union dues going from 500 to 520, and because she never sent receipts for the original $500, she has to send those as well as the new slip.
How far back you can go
You can ask by mail to change returns for 2015 or earlier, but the CRA won't issue a refund for an adjustment request made more than 10 calendar years after the end of the tax year. So a forgotten deduction from a decade ago may correct your record without putting anything back in your pocket.
Where to send it
The back of the form lists the tax centres by tax services office. Residents of Alberta, British Columbia, Manitoba and several other areas use the Winnipeg Tax Centre; much of Ontario and Atlantic Canada uses the Sudbury Tax Centre; much of Quebec uses Jonquiere. Deemed residents, non-residents and new or returning residents use Winnipeg if they live in Denmark, France, the Netherlands, the United Kingdom or the USA, and Sudbury for all other countries.
If the change is because of a slip that arrived late, such as a T4 slip, check you've got every slip for the year before you send the request, so you only change the return once. Changes to an RRSP deduction often follow a new RRSP deduction limit on your notice of assessment.
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The verdict
Treat T1-ADJ as the last resort, not the first. Wait for your notice of assessment, try Change my Return or ReFILE, and only reach for the paper form when your return falls into one of the exceptions. When you do, send one form per year, show previous, change and revised amounts, and include receipts for the whole revised figure.
Frequently asked questions
How long does a T1-ADJ take to process?
The CRA says the webform or paper T1-ADJ may take 19 weeks to process. Online changes through Change my Return or ReFILE are quoted at 2 weeks.
Do I need a separate T1-ADJ for each year?
Yes. Complete a separate form for each tax year you want to change.
Can I change my address with a T1-ADJ?
No. You can't use a return change to update your mailing address, direct deposit, marital status or name.
How far back can I change a Canadian tax return?
You can request changes by mail for older years, but a refund can't be issued for a request made more than 10 calendar years after the end of the tax year.
Can someone else send a T1-ADJ for me?
Yes, if they're authorized. They need Form AUT-01 on file with Option 2 access, which allows changes to your account.
