CRA forms
Form T1-ADJ Explained: Changing a Filed Tax Return
2 weeksthe CRA's usual processing time for a change made online. A paper Form T1-ADJ can take 19 weeks or more.
Sources checked October 20263 min read
Key points
- Used to change an individual return after the notice of assessment arrives
- Online changes through My Account or ReFILE are faster and preferred
- One form per tax year, with documents supporting the full revised amount
- No refund can be issued for a request beyond 10 calendar years
When a change is needed
A slip that arrives late, a receipt that turns up after filing, a deduction missed: the fix is an adjustment to the return already filed, not a second return. The CRA asks taxpayers to wait for the notice of assessment on the original return before asking for a change, and to wait for its answer before asking for another.
There are three ways to ask. Change my return, in the CRA's online account, and ReFILE, through certified tax software, are the quickest, and the CRA prefers them. Form T1-ADJ, T1 Adjustment Request, is the paper route, for changes the online services cannot handle.
Filling in the form
The previous amount on the form is the one on the latest notice of assessment, which may differ from the figure originally filed. The form asks for the details of each change, not a recalculation of the tax.
| Area | What it asks |
|---|---|
| Area A | Identification and the tax year being changed; a separate form is needed for each year |
| Area B | The representative making the request, if there is one, with an authorization on file for that year |
| Area C | Each change: the line number and name, the previous amount, the amount of the change and the revised amount |
| Area D | The certification and signature |
Supporting documents, timing and limits
Documents have to support the entire revised amount on a changed line, not only the difference, where they were not sent before. A request without them is likely to be delayed.
The CRA aims to process online changes within about two weeks and paper requests within 19 weeks of receiving them, though some take up to 35 weeks. A request to change an earlier return goes separately from the current year's return, and no refund can be issued for an adjustment request that goes back more than 10 calendar years.
Changes that go the other way
Adjustments are not only for claiming more. Income that was left off, such as a T4 or T5 slip that arrived after filing, should be added the same way. Reporting it before the CRA's own matching finds it avoids a reassessment with interest and, for repeated omissions, a penalty.
Quick answers
Should I file a new return to fix a mistake?
No. Ask for an adjustment to the return already filed, online or with Form T1-ADJ, once the notice of assessment has arrived.
How long does a T1 adjustment take?
About two weeks online. A paper Form T1-ADJ can take 19 weeks, and some requests take up to 35.
How far back can I change a return?
No refund can be issued for an adjustment request that goes back more than 10 calendar years.
Related pages
Official sources
Call or email and we will tell you which records we need and what the work costs, in writing, before anything starts.
Important. This article provides general educational information, not legal or tax advice for a specific business. Rules, administrative policies, rates and deadlines can change. Confirm your facts and current obligations with the responsible government agency and a qualified adviser.