CRA Notice of Reassessment: What Changed and What to Do

What is a notice of reassessment?

CRA sends a notice of assessment after processing a return. A notice of reassessment, often called an NOR, is an updated summary issued only when an already assessed return changes. CRA may make a change after receiving new information, reviewing documents or processing a change you requested. The notice is about the tax year shown on it, not necessarily the year in which it arrived.

The change can increase a refund, reduce it, create a balance owing or leave no amount payable. Start with the actual notice, not an email that merely says new mail is available. You can find current and older notices under Tax returns or Mail in your individual CRA account. Our guide to getting and reading a CRA notice covers the account steps.

Which parts should you read first?

CRA’s notice guide explains what each section means. A practical reading order is:

1. Tax year and issue date: Confirm which return was changed and when the notice was issued.
2. Explanation of changes: Read CRA’s stated reason. It may point to a slip, claim or information request.
3. Tax assessment or reassessment: Compare the line numbers and amounts with your filed return. Your CRA account can show the full line details.
4. Account summary: Check whether CRA now shows a refund, an amount due or a nil balance.
5. Interest or penalty: If either appears, identify it separately from the underlying tax change.

Keep the original assessment, the new notice and the documents for the changed lines together. If the reason is still unclear, use the contact information on the notice or CRA’s official contact page to ask for an explanation. A phone call may clarify the issue, but it does not itself replace a formal objection.

What if the notice shows money owing?

First check the current balance in your CRA account. CRA says a notice can still show an amount due if it was issued before a payment you made was received. If the payment is not yet visible, CRA’s payment confirmation instructions explain how long to allow and how to resolve a payment applied to the wrong place.

If an amount remains due, CRA lists ways to make a full or partial payment. Our payment guide explains the methods without choosing one for you. If you cannot pay in full, CRA also explains how payment arrangements work. A payment decision is separate from deciding whether the reassessment is correct.

Should you request a change or file an objection?

If you forgot a slip, entered an amount incorrectly or left out information, CRA directs you to change the assessed return. Read our return-change guide for that route. Do not simply send the same return again.

If the information on your return is complete but you disagree with how CRA assessed it, a formal income-tax objection may be the appropriate route. For ordinary individual income-tax objections, CRA’s P148 guide says the deadline is the later of one year after the return’s filing deadline and 90 days after the notice date. Other categories have different rules. The objection guide explains how to check and protect the applicable deadline.

Do not assume that calling CRA, sending documents or requesting a change pauses an objection deadline. If time is short or the tax issue is complex, check the official objection instructions promptly and consider independent professional help.

A simple example of the decision path

Suppose a notice changes a deduction you claimed because CRA says it did not receive a supporting document. Compare the revised line with your return and find the document in your records. If you originally entered the wrong amount, the return-change process may be the useful next step. If you entered the right amount and disagree with CRA’s decision, read the objection instructions and check the deadline while you gather support. This example does not decide which route applies to a real file.

Common mistakes to avoid

• Reading only the amount due: The explanation and changed line numbers tell you what needs attention.
• Paying twice: A notice may have been prepared before your earlier payment reached CRA’s account.
• Assuming every notice needs an objection: Missing or incorrect information can call for a return change instead.
• Assuming every objection has a simple 90-day deadline: For many individuals the later-of rule applies, with exceptions.
• Waiting for an informal reply: A call or adjustment request does not automatically preserve an objection right.