The CRA Notice of Assessment: Reading It, Disputing It, Tracking It
reading an NOA, the 90-day objection window, and the reassessment period firms diarise
A notice of assessment (NOA) is the Canada Revenue Agency's summary of a filed return: income assessed, tax owing or refunded, and carry-forward amounts such as RRSP room. It is not always a copy of what was filed — the CRA may change figures and explains why on the notice. A taxpayer who disagrees generally has 90 days from the NOA date to file a notice of objection.
What is a notice of assessment?
The Canada Revenue Agency's official record of what it assessed from a filed return: total income, taxable income, tax payable, and the resulting refund or balance owing. One is issued for every T1 and T2 the CRA processes, whether or not anything changed.
It arrives by mail or electronically — in CRA My Account for individuals, My Business Account for corporations, and through Represent a Client for authorised firms. Preparers filing electronically can receive an Express NOA delivered directly into their certified software shortly after the return is assessed.
How do you read an NOA?
Top down. The account summary states the result — refund, balance owing, or nil. The assessment detail then sets the CRA's figures beside the filed ones, and an explanation section describes any changes. Carry-forward amounts, including the RRSP deduction limit, follow at the end.
For a firm, the reading order doubles as a checklist: does the result match the filed return, do the changed lines have explanations the client will accept, and did the carry-forward amounts land where next year's file expects them? Five minutes per NOA at receipt beats an hour at next year's preparation.
Why does the NOA differ from the filed return?
Because assessment is a check, not a rubber stamp. The CRA matches the return against slips it holds, corrects calculation errors, and may disallow or adjust claims — each change itemised in the notice's explanation section with the line it touched.
An assessment is also not final acceptance. CRA review programs run after assessment and can ask for support for claims already allowed, and the return remains open to reassessment for years. Treating the NOA as the end of the file, rather than a milestone in it, is how firms get surprised.
How long do you have to dispute an assessment?
Generally 90 days from the date on the notice, by filing a notice of objection. Individuals and graduated rate estates get the later of that 90-day date and one year after the return's filing due date; corporations get the 90 days.
An objection is the formal route — it puts the dispute before the CRA's Appeals Branch and preserves the right to go to the Tax Court of Canada afterwards. For small arithmetic or slip-matching issues, a taxpayer-requested adjustment is often faster; firms reserve objections for disputes about how the law was applied.
How long can the CRA reassess?
Within the normal reassessment period — generally three years from the date of the original notice of assessment for individuals and Canadian-controlled private corporations, and four years for most other corporations. Outside that window, reassessment requires misrepresentation, fraud, or a waiver the taxpayer signed.
The period is why firms keep support on file well after assessment, and why a clean NOA does not close the retention clock on working papers and source documents.
How firms track assessments across a client base
Every NOA starts a clock, so firms log each notice against the client record when it arrives: the date, the result, whether it matched the filed return, and — where a dispute is live — the objection deadline as a tracked date with a named owner.
Clients in Quebec add a second stream: Revenu Québec issues its own notice for the provincial TP-1 return, so each Québec file has two assessments to reconcile and two possible dispute clocks. Firms in this position typically make NOA review a standing task in the post-filing stage of every engagement rather than an ad-hoc habit.
Frequently asked questions
How do you get a copy of a client's notice of assessment?
Authorised representatives can view and download a client's NOA through the CRA's Represent a Client service, and the client can retrieve it in CRA My Account. Preparers who file electronically can receive an Express NOA directly in their certified tax software shortly after assessment. Paper notices still arrive by mail where the client has not chosen online-only correspondence.
What is the difference between a notice of assessment and a notice of reassessment?
A notice of assessment is the CRA's initial processing of a filed return; a notice of reassessment is a later revision of that assessment, issued after a review, an adjustment request, or new information. A reassessment replaces the earlier figures and starts a fresh 90-day objection window for the items it changes.
Does a refund mean the CRA accepted the return as filed?
No. Assessment is initial processing, not final acceptance. CRA review programs operate after assessment and can request support for claims already allowed, and the return remains open to reassessment for the normal reassessment period — generally three years from the original NOA for individuals. Firms keep the file's support intact long after the refund clears.
How long do you have to object to a CRA assessment?
Generally 90 days from the date on the notice of assessment. Individuals and graduated rate estates have until the later of 90 days after the NOA and one year after the return's filing due date; corporations have the 90 days. The CRA can extend the deadline in limited circumstances on application, but no firm should plan on it.
Why should a client keep their notice of assessment?
Because other processes depend on it. Lenders ask for it as proof of income, the RRSP deduction limit for next year is printed on it, and carry-forward amounts flow from it into the next return. Firms keep each NOA on the client record so next season's file starts from the CRA's numbers, not the client's memory.
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