If you disagree with a Canadian income-tax assessment or reassessment, the first formal step is usually a notice of objection to the Canada Revenue Agency (CRA), not a court appeal. Your filing should identify the disputed items, explain why the assessment is wrong, set out the relevant facts, and include documents that support your position. The deadline depends on your taxpayer category and the dates on your assessment notice.
The title of this article does not identify a country. The deadlines and forms below are Canada-specific. Do not apply them to a U.S. or other country’s return; confirm the rules with that country’s tax authority. In Canada, check the notice date, determine whether you are an individual, corporation, trust or another taxpayer, and file as soon as possible. The CRA’s guide states: “You should file your objection as soon as possible.”
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First confirm that the Canadian objection process applies
An income-tax “appeal” can mean different things. In Canada, a dispute normally moves through two stages:
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- Tax Court appeal: if you remain dissatisfied with the CRA’s objection decision, you may take the dispute to the Tax Court of Canada, subject to its filing rules and deadlines.
These are separate filings. Sending a notice of objection is not the same as filing a notice of appeal with the Court. The material below addresses the Canadian federal income-tax process. Provincial taxes, payroll assessments, sales taxes and benefits can have different procedures, even when the CRA is involved.
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Decide whether you need a correction or a formal objection
Before preparing an objection, identify what went wrong. CRA guidance distinguishes between an incomplete or incorrect return and a disagreement with the CRA’s treatment.
Use a return-change process for an omission or entry error
If you left out information, entered an amount incorrectly or otherwise need to correct information you reported, changing the return may be the appropriate route. A correction request is not a substitute for an objection when the return is complete and your position is that the CRA applied the law incorrectly.
Use an objection when you disagree with the assessment
A formal objection is generally appropriate when the reported information is complete but you dispute the CRA’s interpretation, calculation or adjustment. Examples include disagreement over whether an expense is deductible, how income was characterized, or whether a credit was denied. Your objection should identify the exact assessment items and the result you want changed.
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The CRA expects more than a bare statement that an assessment is unfair. Prepare a coherent explanation and evidence that connects each disputed item to the facts.
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1. Assessment or reassessment notice
Locate the notice of assessment or reassessment and record when it was sent. The notice identifies the tax year, adjustments, balance, credits and other information needed to define the dispute. The statutory period is tied to the notice being sent, while public guidance may describe the calculation using the notice date. Preserve the original notice and verify the precise date and counting rule for your case.
2. Your taxpayer classification
Write down whether the filer is an individual, corporation, trust, graduated rate estate or another category. The ordinary objection periods are not identical. A deadline that applies to an individual cannot automatically be used for a corporation or trust.
3. A written statement of disagreement
Set out:
- the tax year and assessment or reassessment being challenged;
- each line, adjustment or issue in dispute;
- the outcome requested, such as allowing a deduction or restoring a credit;
- why the CRA’s treatment is incorrect;
- the relevant facts, in chronological order where timing matters; and
- the legal or factual basis for your position, stated plainly and accurately.
The Income Tax Act requires the notice of objection to set out the reasons and all relevant facts. A form with no explanation may not adequately preserve your position.
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4. Supporting records
Attach documents that prove or clarify the facts for the issue in dispute. Depending on the adjustment, that can include receipts, invoices, contracts, statements, travel or mileage records, employment documents, investment records, correspondence, calculations and schedules. Include only material relevant to the disputed items, label it clearly, and explain in your narrative what each document demonstrates. Keep the originals and a complete copy of everything submitted.
5. Filing and identity details
Have your identification and contact information ready, along with the tax year and notice details. If a representative is filing for you, confirm the representative’s authority and ensure that the submission identifies the taxpayer correctly. A mismatch in the taxpayer name, account or year can delay routing and review.
Canadian objection deadlines by taxpayer type
The ordinary periods below come from the Income Tax Act and CRA guidance. Statutory exceptions, special assessments and individual circumstances can change the result. Use the notice and current legislation to calculate the actual last day.
| Taxpayer or situation | Ordinary period described in Canadian rules | What to verify |
|---|---|---|
| Individual other than a trust or graduated rate estate | The later of one year after the return’s filing-due date for the year and 90 days after the assessment notice was sent. | Confirm the filing-due date for that return, the notice-sent date and whether a statutory exception applies. |
| Corporation | Generally 90 days after the assessment notice was sent. | Check the corporation’s tax year, the notice-sent date and any provision that changes the ordinary period. |
| Trust, graduated rate estate or another taxpayer category | Do not assume the individual or corporate period. The applicable period depends on the category and statutory rules. | Identify the legal status and check the current CRA guidance and Income Tax Act provision that governs it. |
For an individual, the “later of” test can produce a date different from the date you would get by simply adding 90 days to the notice. Compare both statutory dates rather than choosing the one that seems more convenient. For a corporation and many other cases, the ordinary rule is 90 days from when the notice was sent, but that is not a universal rule for every taxpayer.
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- Read the notice and record the date it was sent, not merely the date you opened it.
- Identify the return’s filing-due date and your taxpayer category.
- Calculate each candidate period required by the applicable rule.
- For an individual subject to the “later of” test, use the later date.
- Check the current statute and CRA instructions for exceptions, special assessments and the method of counting days.
- File before the calculated date and retain proof of delivery or electronic confirmation.
If the notice date is unclear, contact the CRA or obtain professional advice immediately. Do not wait for clarification until the final days.
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How to file a notice of objection
The CRA describes secure online filing for eligible filers and paper routes using Form T400A or a signed letter.
- Choose the channel. Use the CRA secure portal when it is available for your account, or prepare Form T400A or a signed letter for submission by mail or fax as described in the current CRA guide.
- Identify the assessment. State the taxpayer’s name and account details, the tax year, and the date and type of notice being challenged.
- List every issue. Separate disputed adjustments rather than describing the disagreement generally.
- Explain the reasons and facts. Connect each requested change to the evidence and explain why the CRA’s adjustment should be reversed or changed.
- Attach relevant documents. Organize attachments with labels or an index so the reviewer can match them to the issues.
- Sign and submit. A paper objection should be signed. Submit through the selected channel before the deadline.
- Keep a complete record. Save the final objection, attachments, transmission receipt, fax confirmation or portal acknowledgement, and the assessment notice in one file.
Online filing can provide an immediate submission record, but a confirmation screen is not a reason to omit your own copy. For mail or fax, use the current destination and instructions in the CRA guide; addresses and procedures can change.
What happens after the objection
The CRA reviews the issues and supporting material, may request additional information, and then issues an objection decision. Respond to requests by the stated date and provide only information relevant to the issues under review. Keep copies of later correspondence and note when each item was sent.
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If you disagree with the CRA’s objection decision, the next stage is a notice of appeal to the Tax Court of Canada. The CRA guide says the Court must receive the notice of appeal within 90 days after the CRA sends its decision. This is a court filing, not another CRA objection, so use the Court’s current forms and filing instructions and preserve evidence of receipt.
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The CRA guide also describes a route to the Tax Court when the CRA has not issued an objection decision within the waiting period specified in the applicable rules. Because the relevant period and conditions depend on the case, check the current guide and legislation before using that route.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.If you missed the objection deadline
A late objection is not automatically accepted. Canadian rules provide an extension process in qualifying circumstances, but eligibility is conditional. Apply promptly and explain the facts and reasons for the delay, along with the underlying objection and supporting evidence. A request for more time does not guarantee that the CRA will grant it.
Even if you believe the deadline has passed, prepare the substantive objection and seek advice immediately. Waiting can make an extension request harder to justify and can create additional court-deadline problems if the CRA has already issued a decision.
Common mistakes and how to avoid them
- Using the wrong country’s deadline: Canadian periods do not apply to U.S. or other foreign assessments.
- Calling every dispute an “appeal”: Start with the CRA objection unless you are already challenging an objection decision in Tax Court.
- Counting from the day you read the notice: The rules refer to when the notice was sent. Preserve the notice and resolve any date uncertainty.
- Applying the individual rule to a corporation or trust: Confirm the taxpayer category first.
- Submitting conclusions without facts: State the reasons and all relevant facts and tie them to documents.
- Leaving out an issue: List every adjustment you want reviewed; do not assume a general complaint covers omitted items.
- Failing to keep proof: Save the signed submission and evidence of online, fax or mail delivery.
- Waiting for a perfect package: File on time with a clear, substantive explanation, then respond to lawful requests for additional information.
When professional help is sensible
Consider a Canadian tax accountant or tax lawyer with assessment-dispute experience when the amount is significant, several years or entities are involved, the issue turns on complex law, the CRA alleges misrepresentation or penalties, records are incomplete, or a Tax Court appeal is being considered. An authorized representative can communicate with the CRA, but you remain responsible for understanding the filing and any deadline.
For a straightforward error, a carefully organized objection may be manageable without representation. Complexity, not merely the size of the tax bill, is the better test: a small adjustment involving an important legal issue can still require specialist advice.
A practical filing checklist
- Country and tax authority confirmed as Canada and the CRA.
- Notice of assessment or reassessment located and notice-sent date recorded.
- Taxpayer type identified.
- Return correction considered and ruled out, if the issue is a disagreement rather than an omitted or incorrect entry.
- Each disputed adjustment and requested outcome listed.
- Reasons and all relevant facts written clearly.
- Supporting documents labelled and attached.
- Applicable deadline calculated under the correct taxpayer rule.
- Form T400A, signed letter or eligible secure-portal submission prepared.
- Submission made before the deadline, with confirmation and a complete copy retained.
- Any CRA follow-up tracked by date.
- If late, extension eligibility reviewed and an application prepared promptly.
Bottom line
For a Canadian income-tax assessment, begin with a CRA notice of objection unless you are correcting an incomplete return or have already reached the Tax Court stage. Individuals other than trusts and graduated rate estates generally use the later of one year after the return’s filing-due date or 90 days after the notice was sent; corporations generally have 90 days from the notice being sent. Because categories and exceptions matter, verify the rule against the actual notice and current law, file a reasoned objection with relevant evidence, and keep proof that it was submitted on time.
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