Guide to the T1 Adjustment Request (T1-ADJ): How to Fix

What Is a T1 Adjustment Request?

Quick tip: download the official T2202 first, then fill it while following this guide: Download T2202 form (official CRA).

A T1 Adjustment Request (Form T1-ADJ) is the way you ask the Canada Revenue Agency (CRA) to make changes to a tax return you've already filed and that has been assessed. Perhaps you forgot to claim a deduction, received a late tax slip, made a math error, or need to add income you overlooked. Rather than filing a whole new tax return, you submit a T1-ADJ to correct specific lines.

The CRA will review your request and issue a Notice of Reassessment if the changes are accepted. This could result in a larger refund, a reduced balance owing, or occasionally, additional tax owed.

When Should You File a T1-ADJ?

Common reasons newcomers file T1 adjustment requests:

• Forgot to claim a deduction or credit: For example, you forgot to claim tuition (T2202), moving expenses, or the disability tax credit.
• Received a late tax slip: Your employer or bank sent a T4 or T5 after you already filed.
• Forgot to report income: You had a second job and didn't report the T4, or you had foreign income you overlooked.
• Made an error: You entered the wrong amount on a line, or missed attaching a required schedule.
• Change in circumstances: For example, your marital status changed and you need to update your return to reflect that.
• Forgot to report your date of entry: If you're a newcomer and didn't indicate your date of entry to Canada on your first return.

Newcomer tip: It's very common for newcomers to make mistakes on their first Canadian tax return. The adjustment process exists specifically for this — don't worry if you need to use it. It's much better to correct an error than to leave it.

Time Limits

You can request an adjustment for a tax return going back up to 10 calendar years. For example, in 2026, you can request changes to returns from 2016 onward. However, the sooner you request the adjustment, the better — especially if it results in a refund or affects your benefit payments.

Three Ways to Submit a T1 Adjustment

Option 1: CRA My Account (Fastest)

The quickest way is through Change My Return in CRA My Account:

1. Log in to CRA My Account
2. Select "Change my return" from the left menu
3. Choose the tax year you want to change
4. Select the line(s) you want to change
5. Enter the corrected amount(s) and provide an explanation
6. Submit

Changes submitted through My Account are typically processed within 2 weeks. This feature is available for the most recent 10 tax years.

Note: You can only use "Change my return" after your original return has been assessed (you've received your Notice of Assessment).

Option 2: ReFILE (Through Tax Software)

If you used NETFILE-certified tax software to file your original return, many software programs support ReFILE, which lets you resubmit specific changed lines electronically. Check if your software supports this feature.

1. Open your tax return in the software
2. Make the corrections
3. Use the ReFILE option to submit the changes

ReFILE is available starting in late March each year for the current and previous tax years.

Option 3: Paper Form T1-ADJ

If you don't have CRA My Account or prefer paper, complete Form T1-ADJ and mail it:

1. Download Form T1-ADJ from canada.ca/forms/t1-adj
2. Fill in your personal information (name, SIN, address)
3. Specify the tax year you want to change
4. For each line you want to change, indicate:
   • The line number
   • The previous amount (what was on your original return)
   • The revised amount (what it should be)
5. Provide a clear explanation of why you're requesting the change
6. Attach any supporting documents (new tax slips, receipts, etc.)
7. Sign and date the form
8. Mail to your designated tax centre

Paper T1-ADJ requests take 8 to 12 weeks to process.

Completing the T1-ADJ Form (Paper) in Detail

Section 1: Identification

• Your full name, SIN, current address, and phone number
• The tax year you want to adjust

Section 2: Changes Requested

This is a table where you list each change:

• Line number: The specific line on the T1 (e.g., Line 10100 for employment income, Line 32300 for tuition)
• Previous amount: What you originally reported
• Revised amount: What it should be

You can request changes to multiple lines on one T1-ADJ.

Section 3: Reason for Change

Explain why you're making each change. Be specific. For example:

• "Received T4 from [Employer Name] after filing. Adding employment income of $3,500 to Line 10100."
• "Forgot to claim tuition credit. Attaching T2202 showing $8,000 in eligible tuition."
• "Incorrectly reported date of entry. Correct date is August 15, 2025."

Section 4: Supporting Documents

Attach copies of any documents that support your changes, such as:

• Tax slips (T4, T5, T2202, etc.)
• Receipts (medical expenses, donations)
• RRSP contribution receipts
• Letters from the CRA or other parties

After You Submit: What Happens Next

1. The CRA reviews your request
2. If approved, they issue a Notice of Reassessment showing the changes and the impact on your tax (refund increase, balance reduction, or additional tax owing)
3. If denied, they'll explain why in a letter. You can appeal if you disagree.
4. If the adjustment results in a refund, it's typically direct-deposited or mailed as a cheque

Tip: After receiving your Notice of Reassessment, review it carefully to make sure the changes match what you requested.

Common Adjustment Scenarios for Newcomers

Scenario 1: Forgot to Report Date of Entry

If you filed your first return without indicating that you were a newcomer to Canada, you should submit a T1-ADJ to add your date of entry. This affects how your income and credits are calculated and may impact your eligibility for benefits like the GST/HST credit.

Scenario 2: Missed Claiming Tuition Credits

If you attended a Canadian institution and forgot to claim your T2202 tuition amounts, submit a T1-ADJ with the T2202 attached. This could create carry-forward tuition amounts that reduce your taxes in future years.

Scenario 3: Late T4 From a Previous Employer

If a former employer sent your T4 late and you'd already filed, you must adjust your return to include the additional income and the tax already deducted (which may increase your refund).

Scenario 4: Forgot to Claim Medical Expenses

If you paid for medical expenses (prescriptions, dental work, vision care) and forgot to claim them, you can adjust your return to add them to Line 33099. You'll need receipts.

Common Mistakes When Filing Adjustments

1. Not waiting for the original assessment: You cannot file an adjustment until your original return has been assessed. Wait for your Notice of Assessment first.
2. Missing supporting documents: Always include supporting documents with paper submissions. Without them, the CRA may deny your request.
3. Adjusting the wrong year: Double-check which tax year you're adjusting. Adjusting 2024 when you meant 2025 creates confusion.
4. Not explaining the reason: A clear explanation speeds up processing and reduces the chance of your request being questioned.
5. Filing a whole new return instead of an adjustment: Do not file a second T1 for the same year. Use the T1-ADJ process instead.

Frequently Asked Questions

Will I be penalized for adjusting my return?

If you're correcting an honest mistake or adding information you forgot, there is generally no penalty. The CRA encourages taxpayers to correct their returns. However, if the adjustment reveals unreported income, interest may be charged on the additional tax owing from the original due date.

Can I adjust a return that's under review or audit?

If the CRA is currently reviewing your return, you may not be able to use "Change my return" online. In this case, submit a paper T1-ADJ or wait until the review is complete.

How many adjustments can I submit for the same year?

There is no limit, but it's best to make all corrections in one request if possible. Multiple adjustments for the same year may trigger additional review.

Making mistakes on your tax return is normal, especially as a newcomer navigating the Canadian tax system for the first time. The T1 adjustment process is straightforward and ensures your tax records are accurate. Whether you use CRA My Account for a quick online change or submit a paper T1-ADJ, the important thing is to correct errors promptly and keep your tax affairs in order.

Download This Form

Before you submit anything, download the latest official file here: Download T2202 form (official CRA). Always use the latest version.

Related internal guides

• IMM 5257 guide
• IMM 1294 guide
• IMM 1295 guide
• IMM 5409 guide
• IMM 5532 guide

Official external resources

• Download T2202 form (official CRA)
• IRCC forms and guides library
• IRCC document checklists
• CRA forms and publications
• IRCC processing times

Related Resources

WelcomeAide Tools

• WelcomeAide Blog — browse all newcomer guides and updates
• Tax Guide — understand taxes, filing deadlines, and common credits
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• Cost Calculator — estimate monthly living costs in Canada
• Benefits Guide — find federal and provincial financial supports

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Official Government Sources

• Canada Revenue Agency (CRA)
• Government of Canada Taxes
• File an Income Tax Return
• Financial Consumer Agency of Canada
• Government of Canada Finance Services
• GST/HST for Businesses