Updated Checked by the Tax-Services.ca editorial team How we check
An income tax assessment is the CRA’s answer to your return. It’s called a notice of assessment, and it tells you what tax you owe or what refund you get, line by line. If you filed electronically, it’s usually available in your CRA account as soon as the return is processed. Read it, and keep it. It’s the paper you’ll want if anything about your tax gets questioned later.
Most notices are dull. That’s the good outcome. The trouble starts when the numbers on it don’t match what you filed.
What does a notice of assessment (NOA) show?
The notice includes your name and address, the last four digits of your SIN, the assessment date and an account summary that says refund or balance owing. Below that comes the calculation, line by line. It also carries an eight-character NETFILE access code.
| Part of the notice | What to check |
|---|---|
| Account summary | Refund or balance owing matches what you expected |
| Line-by-line amounts | Each line equals what you reported |
| Explanation of changes | Any line the CRA adjusted, and why |
| NETFILE access code | Present on the notice, so note where it is |
Compare the notice with your copy of the return. Agree? Then you’re done. If a line differs, the explanation section says what the CRA changed. To sanity-check your expected result before you file, try the tax refund calculator.
A quick way to read it: find the total income line and the refund or balance, then look at the explanation of changes only if they differ from your own copy. Ten minutes at the kitchen table is enough for most households, and the habit pays off the one year something is different.
What does the NOA show about your RRSP, HBP and LLP?
If you contribute to registered plans, the notice of assessment carries extra statements. The RRSP statement gives your deduction limit for next year and your available contribution room, which is the deduction limit minus unused contributions from past years. Contributions above your limit may be taxable.
The Home Buyers' Plan (HBP) statement shows your remaining repayment balance and the minimum repayment you owe, and any shortfall is added to your income as RRSP income. The Lifelong Learning Plan (LLP) statement works the same way. If you have a First Home Savings Account, its statement shows your participation room for next year and the unused contributions you can deduct in future years.
These statements are one reason to keep every NOA. The figures on last year's notice are the starting point for the next contribution.
When will you receive your NOA from the Canada Revenue Agency?
Once the Canada Revenue Agency (CRA) has processed your return, the NOA appears in your CRA account, usually right away. By default the CRA sends the notice as online mail, with an email alert if it has your address. You get a paper copy only if you choose letter mail or the CRA has no email address for you.
Processing takes longer if you file late, the CRA reviews your return, you file certain special returns such as one for a deceased taxpayer, or the CRA asks for more information. When the CRA changes an assessed return, it sends a notice of reassessment (NOR) once the reassessment is complete. It sends an NOR only when something changed.
How do you get your assessment?
The CRA says to sign in to your CRA account, and that is the quick route. You can also see notices from earlier years there. If you can’t get online, you can ask for a paper copy by calling 1-800-959-8281. Paper returns take longer to process, and so does a return that was filed late or is under review.
In your account, choose your Individual account, then Tax returns or Mail, and open the notice you need. The CRA says it sends mail online by default, and it mails notices only if you chose paper or never gave it an email address. So don’t wait for the mail. The phone number is 1-800-959-8281, and the CRA may ask you to verify your identity first.
What if the assessment is wrong?
There are two paths, and they aren’t the same. If you left something out, such as an RRSP receipt or a slip, you ask the CRA to change your return. If the CRA changed something and you disagree even with complete information, you file a formal dispute. The CRA's page on notices says you have 90 days from the date of the notice to register a formal dispute. Its objection guide adds that for individuals the deadline is the later of one year after the filing due date for that return or 90 days from the date on the notice, so check both dates.
To change a return you need your notice of assessment first. Use “Change my return” in your CRA account, or the ReFILE feature in certified tax software, and the CRA lists about two weeks for online requests. By mail you send form T1-ADJ, and the CRA lists 20 weeks, with complex requests taking up to 36. Complex means things like several returns, years past the normal three year reassessment period, or a deceased taxpayer. The Taxpayers' Ombudsperson announced in June 2026 an examination of delays on complex adjustment requests, so allow extra time. The CRA won’t issue a refund for an adjustment requested more than 10 calendar years after the end of the tax year. The CRA’s page on changing a tax return (dated October 30, 2026) lists each route.
Here’s what a missed slip is worth. Say you earn $70,000 in Ontario and forget a $2,000 RRSP receipt. Your taxable income should have been $68,000 (before other deductions). Our engine puts the tax difference on $2,000 at about $593, which is 29.65% at that income. It’s a rough figure without other credits. The RRSP calculator and the marginal tax rate calculator show how the number moves at other incomes.
What is a notice of reassessment?
It looks like the first notice and it means the CRA or you changed the return after it was assessed. The CRA only sends one when something changed. For individuals, the normal reassessment period is three years from the mailing date of the original notice, though the CRA can go back further where there’s neglect, carelessness or fraud.
So keep your receipts at least until those three years have passed, and check the CRA’s record-keeping page for the exact rule. A reassessment isn’t automatically an audit. A late slip or your own correction can trigger one.
What should you do with the notice afterward?
Save it. Download the PDF from your CRA account, or file the paper copy with the return it belongs to. Next spring, the figures on it help with things like RRSP room and carry-forward amounts, and a preparer may ask for it to get access to your account. If you move, update your address with the CRA so later notices reach you. Our guide to dealing with the CRA covers what to do when a letter shows up that you didn’t expect.
Mistakes that cost people money
Ignoring the notice is the first. Balances owing don’t disappear because you didn’t open it. The second is assuming a low refund means you did something wrong. The refund depends on how much tax was taken off during the year and on credits, and the income tax calculator shows the tax on your income so you can compare it with what came off your pay.
The third is filing a fix through the wrong channel. A dispute and a change request are different things, and only one of them has an objection deadline.
How we checked the figures
We checked these pages in November 2026. The contents of the notice, how to get it and the 90 day dispute period come from the CRA's page on notices of assessment. The processing times and the 10 year limit come from its page on changing a return, and the one year rule from the CRA's guide on objection rights (P148). The three year reassessment period comes from CRA guidance for individuals. The tax example uses our 2026 federal and Ontario rates. This is an independent guide, separate from any government body.
Frequently asked questions
What is an income tax assessment?
It is the CRA's processed result of your return, shown on a notice of assessment. It lists your refund or balance owing, the line-by-line amounts it used, any changes it made and why, and your eight-character NETFILE access code. Keep it with your copy of the return.
How long do I have to dispute an assessment?
The CRA says you have 90 days from the date on the notice to register a formal dispute. For individuals its objection guide says the deadline is the later of that date and one year after the return's filing due date. If your information was missing, change the return instead.
How do I change a return after I get my assessment?
Wait for the notice first. Then use Change my return in your CRA account, ReFILE in certified tax software, or mail form T1-ADJ. The CRA lists about 2 weeks for online requests and 20 weeks by mail, with complex requests taking up to 36 weeks.
What is a notice of reassessment?
It is an updated notice the CRA sends when it or you changed the return after the first assessment. It looks like the first notice and explains what changed. A reassessment is not automatically an audit, since a late slip or your own correction can trigger one.
How far back can the CRA reassess an individual?
The normal period is three years from the mailing date of the original notice. The CRA can go further back if there is neglect, carelessness, wilful default or fraud. Keep your receipts and slips at least until that three year window has passed.
How do I get a copy of my notice of assessment?
Sign in to your CRA account, choose your Individual account, then Tax returns or Mail. You can see notices from earlier years there too. If you cannot get online, call 1-800-959-8281 and ask for a paper copy, and expect the CRA to ask you to verify your identity.
- How to file your tax return in Canada: steps and dates
What to gather, when your return is due and how to file in Canada, from the first slip to the notice of assessment that closes the year