Your CRA notice of assessment — line by line

A notice of assessment lands, the number at the top is not the number you expected, and the instinct is either to panic or to file it. Neither helps. The notice is a short, structured document, and once you know what each block is doing you can check it against your return in a few minutes.

What a notice of assessment actually is

The notice of assessment (NOA) is the CRA’s summary of the amounts it calculated from the return you filed. A notice of reassessment (NOR) is the same document reissued after something changed — either because you asked for an adjustment or because the CRA did. Both are issued into your CRA account once the return is processed, and both are worth keeping: the notice is what banks and lenders ask for as proof of income, and it carries the figures you need for next year’s return.

An assessment is not the CRA’s final word. It is the agency’s first pass, made from the return you sent and the data it already holds. It can be reviewed later, and you can dispute it.

Reading it block by block

Notice details

The header block carries the tax year being assessed, the date the notice was issued and the last digits of your SIN or account number. Two of those matter more than they look. The tax year tells you which return you are looking at — if you filed several years at once, the CRA assesses them concurrently and the combined result appears on the last notice of the series. The date the notice was issued is the clock that starts every dispute deadline, so it is the date to write down.

Account summary

This is the answer block, and it has exactly three possible outcomes: a refund, an amount due, or a balance of nil. It can also fold in the result of concurrent assessments and any balance carried over from a previous year, which is the usual explanation when a notice shows more owing than the single return you just filed would produce.

Tax assessment summary

Here the CRA lists the key line numbers and the amounts it used. This is the part to compare directly against your own copy of the return. Go line by line: if the CRA’s number for a line matches yours, that line was accepted as filed. If it does not, something was changed — and the next section tells you what.

Explanation of changes

Any correction the CRA made is described here, usually in a short paragraph tied to a line number. Changes come from two places: information you sent with the return, and information the CRA already had on file, such as slips filed by an employer or a payer. A slip you forgot is the single most common cause of an unexpected change.

RRSP and registered plan statements

On a personal notice you will also find your RRSP deduction limit and available contribution room for the coming year, and, if it applies, a Home Buyers’ Plan statement showing the balance still to repay. These are forward-looking figures, not part of this year’s assessment, but they are the numbers to use when planning contributions.

What to do when the number is wrong

There is an order to this, and skipping steps costs time.

1. Compare first. Pull your filed return and match it line by line to the assessment summary. Most surprises resolve here — a missed slip, a transposed figure, a credit claimed twice.
2. If you left something out, adjust. An omission or an error on your side is an adjustment request, not a dispute. That is a different and much faster process than objecting.
3. If the CRA got it wrong, call before you object. Many disagreements are a misunderstanding that a phone call to the number on the notice clears up.
4. If it still stands, object formally. That is a notice of objection, and it is time-limited from the date on your notice.

Why a notice can take longer than usual

If your assessment has not arrived, the common reasons are that the return was filed after the due date, that the CRA is running a review of the return, that more than one return was filed at once, or that the CRA has asked you or your representative for more documents. A review is not an audit — it is a request for support behind a claim, and it is described in our guide to CRA reviews and audits.

Corporate notices are the same idea

An incorporated business gets an assessment for its T2 in the same shape: what was filed, what was changed, and what is owing. The difference is the deadlines around it — corporate filing and payment dates are separate and neither is tied to the assessment date. Those are set out in our guide to T2 deadlines and late-filing penalties, and the fastest way to see your assessed balances in one place is CRA My Business Account.

The bottom line

Read the account summary, then the explanation of changes, then compare the line numbers to your return. That sequence answers almost every question a notice raises. If it does not, note the date on the notice — every remedy runs from it — and get advice before the clock runs out. Handling assessments and CRA correspondence is part of our tax services.

This article is general information for Canadian business owners and is current as of July 2026. It is not tax, legal or accounting advice, and it does not create a client relationship. Tax rules change and your situation is unique — please speak with a CPA before acting on anything here.