The short version
- Individuals can object until the later of one year after the return's filing due date and 90 days after the date on the notice. Corporations and GST/HST have 90 days, full stop.
- Missed it? You can ask CRA for an extension of time, but only within one year after the deadline, and you have to show you couldn't act or always meant to object, and that you asked as soon as you could.
- If CRA refuses the extension, you can ask the Tax Court of Canada to grant it instead.
- Past the extension window, objection rights are gone for that notice. Individuals can still ask CRA to adjust a return up to 10 years back, at CRA's discretion, and anyone can ask for relief from penalties and interest.
- Count from the date printed on the notice, not the day you opened it.
CRA Objection Deadline: Don't Miss It
The objection deadline is the one CRA date that doesn't forgive. Miss a payment and you pay interest. Miss the objection deadline by a year and a day, and CRA's mistake becomes your permanent bill. The calculator above gives your exact date. This page covers the rules behind it and, more usefully, what to do if the date has already gone by.
The Deadlines
| Who or what | Last day to object | Example: notice dated October 1, 2026, for 2025 |
|---|---|---|
| Individuals (T1) | Later of one year after the filing due date and 90 days after the notice | April 30, 2027 (one year after April 30, 2026 beats December 30, 2026) |
| Self-employed individuals | Same, with a June 15 filing due date | June 15, 2027 |
| Graduated rate estates (T3) | Same as individuals | Depends on the estate's due date |
| Corporations (T2) | 90 days after the notice | December 30, 2026 |
| GST/HST | 90 days after the notice | December 30, 2026 |
For a recent reassessment of an old year, the 90-day date usually wins, because the one-year date is long gone. That's the trap: people remember "you have a year" and lose a reassessment of 2022 in March 2027. If CRA reassesses the same year again, a new objection deadline starts for what changed.
Deadline coming up?
The SmartFile reads your notice, confirms your deadline, and drafts the objection so it's filed on time. If the deadline has passed, it drafts the extension request with it.
If You Missed It: The Extension of Time
You can ask CRA to accept a late objection. The request has to be made within one year after the objection deadline, and it must show:
- Why you didn't file on time: during the objection period you were unable to act or to instruct someone to act for you, or you had a real intention to object all along.
- That it's fair: granting the extension would be just and equitable.
- That you didn't sit on it: you made the request as soon as circumstances allowed.
File the request together with the objection itself, through My Account ("Register my formal dispute") or in writing with form T400A, and include evidence: hospital records, proof of a death in the family, a letter to CRA you thought was an objection, a representative who dropped the ball. "I didn't read my mail" rarely works. Mail that went to an old address you never updated usually doesn't either.
If CRA Says No
You can apply to the Tax Court of Canada for the extension, generally within 90 days after CRA refuses it, or after 90 days if CRA hasn't answered. The court applies the same tests. Apply early in the one-year window: the court can't extend past it.
If Even That Window Is Closed
| Option | What it can do |
|---|---|
| Ask CRA to adjust the return (individuals) | CRA can reduce tax or issue a refund for a year up to 10 years back, at its discretion; see changing your return |
| Taxpayer relief | Cancels penalties and interest for extraordinary circumstances, CRA errors or financial hardship. Not the tax itself |
| A new reassessment | If CRA reassesses again, a new objection period opens for the changes |
| Payment arrangement | Spreads out what you owe while you pursue the other options |
Rules That Keep You Inside the Window
- Write the deadline down the day the notice arrives, with a reminder a month before.
- File first, argue later. You can send documents after filing; you can't file after the deadline.
- Waiting for a call back is not a plan. Phone calls don't stop the clock.
- Keep CRA's address for you current, and sign up for online mail.
- Keep proof of the date you filed: the online confirmation or registered mail receipt.
Late-filing penalties and interest are covered on filing taxes late. How to write the objection itself is on CRA objection. If you're reading your notice for the first time, start with notice of reassessment. Everything else is on the CRA guide.
Objection Deadline Questions
What is the deadline to object to a CRA assessment?
For individuals, the later of one year after the return’s filing due date and 90 days after the date on the notice. For corporations and GST/HST, 90 days after the notice.
Can I object after the deadline?
Yes, if you ask for an extension of time within one year after the deadline and show you could not act or intended to object, that it is just and equitable, and that you asked as soon as you could.
What if CRA refuses my extension request?
You can apply to the Tax Court of Canada for the extension, generally within 90 days after CRA’s refusal, or after 90 days if CRA has not responded.
Is the 90 days counted from when I received the notice?
No. It is counted from the date on the notice.
What can I do if it is too late to object?
Individuals can ask CRA to adjust a return up to 10 years back, which CRA may or may not accept, and anyone can ask for taxpayer relief from penalties and interest.
Sources: CRA, Income tax objections decision tree; GST/HST Memorandum 31-0; File an appeal to the Court. Checked October 2026. The extension conditions and Tax Court application timing are summarized from sections 166.1 and 166.2 of the Income Tax Act as we understand them. Example dates do not adjust for weekends.
Last reviewed October 5, 2026 against CRA and Government of Canada sources. How we check our facts.