How to Amend Your Tax Return in Canada 2025 | CRA Adjustment Request Guide

When Should You Amend Your Tax Return?

You should consider amending your tax return if you:

Forgot to claim a deduction – RRSP contributions, childcare expenses, moving expenses
Missed a tax credit – Medical expenses, donations, tuition transfers
Received a late tax slip – T4, T5, T3 that arrived after you filed
Made a calculation error – Wrong amounts entered
Forgot to report income – Better to self-report than wait for CRA
Didn't claim all eligible expenses – Work from home, employment expenses

Important Timing

Wait until you receive your Notice of Assessment (NOA) before submitting an adjustment. CRA processes changes faster once your original return is assessed.

3 Ways to Amend Your Return

Method 1: CRA My Account (Recommended)

The fastest and easiest way to make changes:

Step-by-Step Instructions

1. Log in to CRA My Account at canada.ca
2. Click "Change my return" under Tax Returns
3. Select the tax year you want to change
4. Find the line number(s) you need to change
5. Enter the corrected amounts
6. Explain why you're making the change
7. Submit and save your confirmation number

Processing time: Usually 2 weeks

Method 2: ReFILE (Through Tax Software)

If you used NETFILE-certified software to file your return, you can use ReFILE to submit changes:

Use the same software you originally filed with
Make your corrections directly in the return
Submit via ReFILE option
Available from mid-February to late January of the following year

Method 3: Paper Form T1-ADJ

For those who prefer paper or don't have online access:

Download Form T1-ADJ from CRA website
Complete details of each change
Attach supporting documents (receipts, slips)
Mail to your tax centre
Processing takes 8+ weeks

Processing Times by Method

Method	Processing Time	Best For
CRA My Account	~2 weeks	Most changes, fastest results
ReFILE	~2 weeks	If you have your tax software
T1-ADJ Paper Form	8+ weeks	Complex changes with documents

Common Amendment Scenarios

Claiming Missed RRSP Contributions

One of the most common reasons to amend:

Find your RRSP contribution receipts
Verify contributions were made by the deadline (March 1 for previous tax year)
Adjust Line 20800 (RRSP deduction)
Check your RRSP deduction limit on your NOA

Adding Medical Expenses

Gather all medical receipts
Remember you can claim a 12-month period ending in the tax year
Include prescriptions, dental, vision, travel for medical care
Adjust Line 33099 (for yourself/spouse) or Line 33199 (for dependants)

Claiming Charitable Donations

Donations can be carried forward up to 5 years
Need official receipts from registered charities
Adjust Schedule 9 and Line 34900

Reporting Forgotten Income

Pro Tip: If you forgot to report income, it's better to self-report before CRA contacts you. You may avoid penalties through the Voluntary Disclosures Program, though interest will still apply.

What You'll Need

Information Required

Tax year being amended
Line numbers affected
Original amounts you claimed
New corrected amounts
Clear explanation of why you're making the change

Supporting Documents (Keep These)

T4, T5, T3 slips
RRSP contribution receipts
Medical expense receipts
Donation receipts (official tax receipts only)
T2202 (tuition) forms
Any other relevant receipts

What Happens After You Submit

If Your Refund Increases

CRA sends a Notice of Reassessment
Additional refund deposited to your account (or mailed)
CRA pays interest on refunds owed to you

If You Owe More Tax

CRA sends a Notice of Reassessment with amount owing
Payment due immediately
Interest charges from original filing deadline
Set up a payment plan if needed

What You Cannot Change

Certain elections that are irrevocable once made
Filing status in some situations
Principal residence designation (limited exceptions)
Statute-barred years (beyond 10 years)

Changing Multiple Years

You can submit adjustments for multiple tax years:

Submit a separate request for each year
CRA processes earlier years first
Carryforward amounts (like capital losses) are automatically updated
Each year's change may affect subsequent years

Track Your Adjustment

Monitor your adjustment request:

Log in to CRA My Account
Check "Status of adjustment request"
Watch for Notice of Reassessment in mail/My Account

Don't File a Duplicate Return

Never file a second tax return for the same year. This causes significant processing delays. Always use the adjustment process instead.

Need Help With Your Amendment?

Our AI tax assistant can help you figure out which lines to change and what documentation you need.

Ask the Tax Assistant

Disclaimer: This guide provides general information about amending tax returns in Canada. Complex situations involving significant amounts or multiple years may benefit from professional tax advice.

Good News: Mistakes Can Be Fixed