T1 Personal Tax Return Guide: Filing Your Taxes Right in Canada
Everything you need to know about the T1, from which slips to gather to the 5 most common mistakes a former tax auditor sees on personal returns.
I spent 5 years as a tax auditor. Now that knowledge works for you, not against you.
Ahmed Jama, CPA
What Is a T1 Personal Tax Return?
A T1 personal income tax return is the annual filing Canadian residents submit to CRA to report income, claim deductions and non-refundable credits, and calculate tax owing or refund. The standard filing deadline is April 30, or June 15 if you or your spouse are self-employed. The balance owing is always due April 30 regardless of filing deadline.
- April 30 deadline: Filing and payment due for most individuals.
- June 15 extension: Self-employed filers get extra time, but balance still due April 30.
- NETFILE: Electronic filing — most returns are filed this way.
- Refund or balance owing: Calculated based on income, deductions, and credits.
Who Must File a T1?
You must file a T1 if you owe tax, have self-employment income, want to receive GST/HST credits, want to carry forward losses, or have capital gains or dispositions. Even if none apply, filing is recommended to maintain RRSP room, receive benefits, and build a tax history. Newcomers to Canada must file for the year they become tax residents.
- Tax owing: If you owe tax, filing is mandatory.
- Self-employment: All self-employment income must be reported on T2125.
- Benefits: Filing triggers GST/HST credit, Canada Child Benefit, and other benefits.
- Capital dispositions: All capital gains and losses must be reported, even if no tax is owed.
Key Income Slips
Gather every income slip you received. The most common are T4 (employment), T4A (pension/other), T5 (investment income), T3 (trust income), T5008 (securities), and T4E (EI benefits). Missing a slip is the most common CRA audit trigger — CRA matches slips electronically and will catch omissions.
- T4: Employment income — one per employer.
- T4A: Pension, self-employment commissions, annuity income.
- T5/T3: Investment income — dividends, interest, mutual fund distributions.
- T5008: Securities transactions — capital gains and losses.
- T4E: Employment Insurance benefits.
Deductions vs Credits
Deductions reduce your taxable income dollar-for-dollar (e.g., RRSP contributions, moving expenses). Credits reduce your tax payable at the lowest marginal rate (e.g., tuition, medical, charitable donations). Deductions are generally more valuable for high-income earners. Ahmed optimizes the mix of deductions and credits for your situation.
| Type | How It Works | Examples |
|---|---|---|
| Deduction | Reduces taxable income dollar-for-dollar | RRSP, moving expenses, childcare, spousal support |
| Non-refundable credit | Reduces tax payable at lowest rate (~15%) | Tuition, medical, donations, disability tax credit |
| Refundable credit | Paid even if no tax owing | GST/HST credit, Canada Child Benefit |
NETFILE Requirements
NETFILE is CRA's electronic filing service. Most T1 returns are filed via NETFILE through certified tax software. Some returns cannot be NETFILEd, including bankruptcy filings, returns for deceased persons, and returns with income over $1 million. Ahmed handles electronic filing for all clients.
- Certified software: Returns must be prepared using CRA-certified tax software.
- Most returns eligible: The majority of T1 returns can be NETFILEd.
- Exceptions: Bankruptcy, deceased persons, and income over $1M cannot be NETFILEd.
- Confirmation: CRA sends a confirmation number when the return is accepted.
5 Mistakes a Former Tax Auditor Sees Most
Ahmed spent 5 years as a tax auditor reviewing T1 returns. These are the five most common mistakes he saw — and still sees — that trigger reviews, reassessments, and penalties. Avoiding them from the start is far easier than fixing them after a tax notice arrives.
- 1. Missing slips: Omitting a T5 or T4A because you forgot or didn't receive it — CRA matches electronically and catches this.
- 2. Inflated home office: Claiming home office expenses without a signed T2200 or exceeding the eligible percentage.
- 3. Personal expenses in T2125: Mixing personal expenses into business deductions — the #1 self-employment audit trigger.
- 4. No mileage log: Claiming vehicle expenses without a detailed mileage log — CRA will deny the claim.
- 5. Wrong capital gains inclusion: Applying the old 50% rate to gains that fall under the 2024 2/3 rule above $250,000.
Your Questions, Answered Directly
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