# T1 adjustment request: filling in and mailing Form T1-ADJ

Source: https://canadataxdesk.com/after-you-file/t1-adjustment-request
Publisher: Canada Tax Desk (canadataxdesk.com), independent editorial site
Topic: After You File
Last updated: 2026-09-18

> A T1 adjustment request is the paper route for asking the CRA to change an individual return it has already assessed. You complete Form T1-ADJ, one form per tax year, attach receipts for the full revised amounts, sign it and mail it to your tax centre. It covers cases the online services refuse, but it is slower: expect weeks to months instead of 2 weeks.

## Key facts

- Form: T1-ADJ, T1 Adjustment Request
- One form covers: One tax year only
- Send to: The tax centre listed on the back of the form
- Refund limit: No refund for years more than 10 calendar years back
- Complex requests: Up to 33 weeks (CRA, September 2026)

## What a T1 adjustment request is for

A T1 adjustment request asks the CRA to change specific line amounts on a return it has already assessed. It is not a new return. The form itself says to use it when your change falls into one of the exceptions to the two online services, Change my return in My Account and ReFILE in certified software.

Those exceptions are narrow but real. Paper is the right choice when the return is for 2015 or earlier, a bankruptcy year or a year before it, a deceased person's optional return, a return filed with the wrong province or territory of residence, a return that needed Form T2203 for multiple jurisdictions, or certain international and non-resident returns. You also need paper if you cannot or do not want to use a CRA account.

> **Try online first:** If none of those exceptions applies, [Change my return](https://canadataxdesk.com/after-you-file/change-my-return-cra) or [ReFILE](https://canadataxdesk.com/netfile/refile-cra-amend-return) will usually finish in about 2 weeks. Mailing a T1-ADJ for a simple change mostly adds waiting time.

## How to fill out the T1 adjustment form, area by area

The current T1-ADJ has four areas labelled A to D. Wait until you have the notice of assessment for the year, then work from that notice rather than from your own copy of the return.

1. **Area A, Identification.** Enter your 9-digit social insurance number, the single tax year you want changed, your full name with surname first, and your address. Tick the box if it is the same as on the return.
2. **Area B, Authorization.** Fill this in only if a representative is making the request. They give their RepID or EFILE number, and a Form AUT-01 with access Option 2 must be on file or attached.
3. **Area C, Adjustment details.** For each change, give the line number, the line name, the previous amount, a plus or minus sign, the amount of change and the revised amount. Use the amount on your notice of assessment as the previous amount if the CRA already changed it. Do not recalculate your tax.
4. **Area D, Certification.** You or your representative sign and date the form.

### Worked example: missed medical expenses

Suppose your 2025 net income was $40,000 and you forgot $2,000 of prescription and dental receipts. In Area C you would write line 33099, Medical expenses, previous amount 0, plus, amount of change 2,000, revised amount 2,000. The CRA works out the credit: for 2025 you claim the part above the lesser of 3% of net income ($1,200) or $2,834, so $800 qualifies, worth $116 federally at the 14.5% credit rate.

| Line | Name of line | Previous amount | +/- | Change | Revised amount |
| --- | --- | --- | --- | --- | --- |
| 33099 | Medical expenses | 0 | + | 2,000 | 2,000 |

How the medical expense example appears in Area C

## Supporting documents to attach

The form asks for documents that support the entire revised amount, not just the increase. If you claimed $500 of union dues without receipts and now add $20 from a late T4, you send proof for all $520. Missing paperwork is the main reason a paper request stalls.

- The new or corrected slip, for example a T4, T5 or T4A that arrived after you filed.
- Official receipts for claims such as medical expenses, donations or RRSP contributions.
- Any schedule or form the change relies on, such as Schedule 11 for tuition or Form T2203 for multiple jurisdictions.
- A short explanation in the Other details space, or on an extra sheet, if the reason for the change is not obvious from the slips.

Send photocopies and keep the originals. The CRA says to keep supporting records for at least six years in case it reviews the claim later.

## T1 adjustment mailing address: which tax centre

There is no single T1-ADJ address. The back of the form (edition 23) routes you by the tax services office that serves your area. Check the chart on the copy you download, since the CRA can change routing between editions.

| Tax centre | Mailing address | Serves (examples from the form) |
| --- | --- | --- |
| Winnipeg Tax Centre | Post Office Box 14000, Station Main, Winnipeg MB R3C 3M2 | Alberta, BC, Manitoba, Yukon, NWT, Regina, Saskatoon, London, Hamilton, Windsor, Thunder Bay |
| Sudbury Tax Centre | Post Office Box 20000, Station A, Sudbury ON P3A 5C1 | Toronto offices, Ottawa, Barrie, Kingston, Atlantic provinces, Montréal, Sherbrooke, Outaouais |
| Jonquière Tax Centre | 2251 René-Lévesque Boulevard, Jonquière QC G7S 5J2 | Chicoutimi, Laval, Québec, Montérégie-Rive-Sud, Rimouski, Trois-Rivières, Nunavut |

Tax centres listed on Form T1-ADJ (edition 23)

Non-residents, deemed residents and new or returning residents are routed by country: the form sends residents of Denmark, France, the Netherlands, the United Kingdom and the USA to Winnipeg, and everyone else abroad to Sudbury.

### Is there a T1 adjustment form online?

The CRA's T1-ADJ page offers a web version of the form alongside fillable, standard and large-print PDFs, updated 9 September 2026. The form's instructions still say to send the completed form to your tax centre. If you want a truly online submission, use Change my return or ReFILE instead.

## T1 adjustment processing time and next steps

The CRA publishes different figures on different pages. Its change-your-return page gives 16 weeks for a paper request, its May 2026 tax tip described an 8-week standard for mailed requests, and in September 2026 its processing-times page said complex adjustment requests take up to 33 weeks and that it was seeing higher than normal intake.

| Type of request | Published timeline | Source page |
| --- | --- | --- |
| Online (Change my return or ReFILE) | Within 2 weeks | Change your return |
| Paper T1-ADJ, straightforward | 8 to 16 weeks | May 2026 tax tip; Change your return |
| Complex request needing verification | Up to 33 weeks | Processing times, September 2026 |

Published timelines for T1 adjustment requests

When the CRA finishes, you get a notice of reassessment showing the changes, a reassessment with partial changes and a letter, or a letter refusing the request. If the CRA writes to ask for more documents first, see our [CRA review letter](https://canadataxdesk.com/after-you-file/cra-review-letter) guide. The [after you file guide](https://canadataxdesk.com/after-you-file) shows where a reassessment fits in the wider timeline.

## Common questions

### What is a T1 adjustment request?

It is a request, usually on Form T1-ADJ, asking the CRA to change specific line amounts on an individual return it has already assessed. The CRA replies with a notice of reassessment or a letter explaining its decision.

### Where do I send Form T1-ADJ?

To the tax centre shown for your area on the back of the form: Winnipeg, Sudbury or Jonquière in the current edition. Non-residents are routed by country of residence.

### Can I put two tax years on one T1-ADJ?

No. The form asks you to complete a separate form for each year. Mail them together if you like, but each year needs its own signed form and documents.

### How long does a T1 adjustment take in 2026?

CRA pages give 8 to 16 weeks for a straightforward paper request and up to 33 weeks for complex ones as of September 2026. Online changes are usually done within 2 weeks.

### Do I need to recalculate my tax on the T1-ADJ?

No. The form tells you not to provide a recalculation. List the line changes and the CRA works out the new tax, credits and refund or balance.

### Can my accountant sign the T1-ADJ for me?

Yes, a representative can complete Area B and sign, but the CRA needs a Form AUT-01 with access Option 2 on file or attached so it can make changes to your account.

## Sources

- [Form T1-ADJ, T1 Adjustment Request (CRA)](https://www.canada.ca/en/revenue-agency/services/forms-publications/forms/t1-adj.html)
- [Change your return (CRA)](https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/about-your-tax-return/change-your-return.html)
- [Check CRA processing times](https://www.canada.ca/en/revenue-agency/corporate/contact-information/check-cra-processing-times.html)
- [Making changes to your tax return? (CRA tax tip, May 2026)](https://www.canada.ca/en/revenue-agency/news/newsroom/tax-tips/tax-tips-2026/making-changes-to-your-tax-return-here-what-new-and-how-to-save-time.html)
- [Lines 33099 and 33199, eligible medical expenses (CRA)](https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/about-your-tax-return/tax-return/completing-a-tax-return/deductions-credits-expenses/lines-33099-33199-eligible-medical-expenses-you-claim-on-your-tax-return.html)