Notice of Assessment (2026): The Date Matters More Than the Refund
Most people read it for the refund and file it. The date on it starts your 90-day window to dispute the assessment — and if you're on CRA online mail, it never arrives by post at all.
CreditCardGuru Editorial Team
Rewards & Cards Research · September 1, 2026 · 8 min read
Most people read a notice of assessment for one number — the refund or the amount owing — and file it. The more valuable thing on it is the date.
That date starts the clock on your right to dispute the assessment. It also carries figures that exist nowhere else and that you will need years later.
It is a clock and a record, not a receipt.
What is a notice of assessment?
It is the CRA's summary of the calculated amounts from your income tax and benefit return, sent after your return is processed.
A notice of reassessment is different: the CRA sends one only if changes are made to a return it has already assessed. It is an updated summary of what changed.
Being assessed is not the same as being verified. The CRA assesses returns quickly and may review them later — a refund is not a ruling that everything on your return was correct.
What is actually on it
| Section | What it holds | Why it matters later |
|---|---|---|
| Notice details | Last four digits of your SIN or Temporary Taxation Number, the tax year, and the date the notice was issued | The date starts your dispute window |
| NETFILE access code | An 8-character code of numbers and letters, on the right side of the notice | Used by tax software next year to confirm your identity |
| Account summary | Refund, amount due, or "Balance: Nil" | The number most people read and then stop |
| Tax assessment | The key line numbers and amounts used to assess your return, with an explanation of any changes | Compare against what you filed to spot CRA changes |
| Registered plan information | Carry-forward figures such as your RRSP deduction limit | The authoritative source for next year's contribution |
The NETFILE access code is the one almost nobody notices. The CRA says it is not mandatory, but without it you cannot use information from your most recent return to confirm your identity — the CRA has to authenticate you another way. First-time filers do not have one.
What it does not tell you
Your TFSA contribution room is not what this document is for.
People go looking for it here and do not find it. For TFSA room the CRA directs you to your CRA account — and then tells you not to rely on that either, because it updates only once a year in the spring. See how to work out your actual TFSA room.
Your RRSP deduction limit is a different story. That one is published here, and this is the figure to use rather than calculating 18% of your salary.
The date, and your 90 days
The CRA states: "If the information is complete but you disagree with your assessment or reassessment, you have 90 days from the date of your notice to register a formal dispute." That is from its notices page, last modified July 2025.
Note what the clock runs from — the date of the notice, not the date you opened it, read it, or noticed the problem. If it sat unread in your CRA account for two months, two months are gone.
There is an important distinction before you object:
- If you left something out or entered it wrong — that is not a dispute. You change your return instead, through a return adjustment.
- If the return is complete and you disagree with the CRA's assessment of it — that is an objection, and the 90 days apply.
If you believe you are already past the window, contact the CRA before concluding you have no recourse. There are circumstances in which an extension of time can be applied for, and that is a conversation worth having rather than an assumption worth making.
Where the numbers came from
Three documents, in order, and people routinely confuse them.
| Document | Who produces it | What it is |
|---|---|---|
| T4 and other slips | Your employer, bank or payer | A report of what they paid you and withheld |
| Your tax return | You | Your claim of income, deductions and credits |
| Notice of assessment | The CRA | The CRA's calculated result of that return |
A T4 is an input. The notice is the output. If a figure on your notice looks wrong, the error could be in the slip, in what you entered, or in the CRA's assessment — and which one it is determines whether you adjust your return or file an objection.
A missing slip does not excuse a late return. If a slip has not arrived, you are still expected to report the income — use your own records, such as pay stubs or statements, rather than not filing.
How to get a copy
Online is immediate; by mail you have to phone.
In your CRA account: sign in, select your Individual account, then Tax returns or Mail, then the notice you need. Current and previous years are both available.
For a paper copy, you have to call the CRA and request one. Alternate formats — digital audio, electronic text, braille and large print — can be ordered the same way.
On delivery: the CRA sends online mail by default unless you have set your preference to letter mail or never gave them an email address. If you are on online mail, the notice will not arrive by post at all — you get an email telling you there is mail in your account. That is how notices sit unread while the 90 days run.
What you will need it for
- Proving income. Lenders commonly ask for recent notices of assessment when you apply for a mortgage, and landlords sometimes do for a rental application.
- Next year's RRSP contribution, using the deduction limit printed on it.
- Filing next year, using the NETFILE access code.
- Checking the CRA's work — comparing its line numbers against what you actually filed.
One quirk worth knowing: if your notice was issued before your payment reached the CRA, it can still show a balance owing even though you paid in full. Check the date before panicking.
Everything described here — the sections of the notice, the 8-character NETFILE access code, the delivery methods, how to obtain a copy, and the 90-day dispute window — is from the Canada Revenue Agency's "Notices of assessment – NOA or NOR" page at canada.ca, last modified July 2025 and read September 2026. This page explains a document and names a deadline; it is not tax advice, and a disputed assessment is a matter for the CRA or a tax professional. No product is reviewed and no affiliate links appear.
Frequently asked questions
What is a notice of assessment?
It is the CRA's summary of the calculated amounts from your income tax and benefit return, issued after the return is processed. It confirms your refund or balance owing, shows the line numbers used, and carries carry-forward figures such as your RRSP deduction limit.
How long do I have to dispute my notice of assessment?
The CRA states you have 90 days from the date of your notice to register a formal dispute. The clock runs from the notice date, not from when you read it. If you think you are out of time, contact the CRA rather than assuming the right is gone.
What is the difference between a T4 and a notice of assessment?
A T4 is issued by your employer and reports what they paid you. A notice of assessment is issued by the CRA after you file, and reports its calculation of your return. The slip is an input; the notice is the result.
Where do I find my notice of assessment?
In your CRA account — sign in, select your Individual account, then Tax returns or Mail, and choose the notice. Previous years are there too. For a paper copy you must phone the CRA and request one.
Does my notice of assessment show my TFSA room?
No. For TFSA contribution room the CRA points you to your CRA account, and warns that figure updates only once a year in the spring. Your RRSP deduction limit, by contrast, does appear on the notice.
What is the NETFILE access code on my notice?
An 8-character code of numbers and letters on the right side of the notice, used by tax software to confirm your identity when filing. It is not mandatory, but without it the CRA has to authenticate you another way. First-time filers do not have one.
What is a notice of reassessment?
An updated summary the CRA sends only when changes are made to a return it already assessed. Receiving one does not necessarily mean you did something wrong — it means the assessed figures changed, and the notice explains what changed.
My notice shows a balance owing but I already paid — why?
Probably timing. The CRA notes that if your notice was issued before your payment was received, it may still show a balance even though you paid in full. Check the notice date against the date your payment went out.
Do I need my notice of assessment for a mortgage?
Lenders commonly ask for recent notices of assessment as proof of income, particularly if you are self-employed. Requirements vary by lender, so ask yours what it needs rather than assuming. You can download previous years from your CRA account.
My employer never sent my T4 — can I still file?
Yes, and you should. A missing slip does not push back the filing deadline. Report the income using your own records — pay stubs or bank statements — and contact your employer and the CRA about the missing slip separately.