Updated Checked by the Tax-Services.ca editorial team How we check
To estimate your tax return, take your income, work out the tax on it, and subtract what was already withheld. If the withholding is bigger you get a refund, and if it’s smaller you owe the gap. A single Ontario worker with a $75,000 salary and $13,000 withheld should expect about $295 back, going by this site’s 2026 engine.
How do I estimate my tax return in three numbers?
You need your income, your deductions and your tax already paid. Your T4 shows employment income in box 14 and tax taken off in box 22, and the CRA tells you to report the box 14 total on line 10100. Deductions are things like RRSP contributions, child care costs and union dues. Put those into the tax refund calculator, pick your province and read the answer.
The result is a refund or a balance owing. It’s an estimate, a ballpark rather than a promise. It counts the basic personal amount, the Canada employment amount and the CPP and EI credits, and leaves out most other claims.
What does the same salary give at different withholding levels?
Withholding is the number people can’t easily guess. On a $75,000 Ontario salary the engine puts the year’s income tax at $12,704.65. Here’s what different T4 amounts would mean.
| Tax withheld (box 22) | Estimated result |
|---|---|
| $10,000 | $2,704.65 owing |
| $11,000 | $1,704.65 owing |
| $12,000 | $704.65 owing |
| $13,000 | $295.35 refund |
So a $75,000 salary can produce either result. What matters is what your employer withheld, and that can be off by thousands from your real tax bill in either direction, so one T4 on its own tells you nothing until you run the numbers.
Can I do it by hand in five minutes?
Pretty much. Write down total income from every slip, subtract the deductions you plan to claim, and that’s your taxable income. Work out the tax on it, then subtract the credits you know you qualify for. Whatever is left is your tax for the year. Take away the box 22 amounts from all your slips and you have the answer: positive means you owe, negative means a refund.
Take Priya in Mississauga, who has the $75,000 salary above. Her T4 says $12,000 was withheld. The year’s tax is $12,704.65, so she’s looking at $704.65 owing, not a refund. Knowing that in March is much nicer than finding out at tax time in a rush.
Can an RRSP contribution change my refund?
Yes, and it’s the lever most people can still pull. Put $5,000 into an RRSP and claim it on the same $75,000 salary, and the engine’s income tax falls from $12,704.65 to $11,072.15. That’s $1,632.50 less, about 32.7 cents on each dollar. The exact saving depends on your bracket. Use the RRSP calculator to see the effect for your own income.
Check your limit first. It’s on your last notice of assessment and in your CRA account, and going over it costs you. Our guide to the notice of assessment shows where to find it.
What if my income comes from more than a job?
Then the T4 isn’t the whole story. Interest, rent, dividends and capital gains all add to taxable income, and none of them has tax withheld at source. Run the income tax calculator with those fields filled in, then compare its total with what you’ve already paid.
Self-employed? Nobody withholds anything, so your estimate is the whole bill, and the self-employed tax calculator is the better start. It lowers income tax for your deductions but doesn’t lower CPP, and it leaves out EI, so treat the result as a floor rather than an exact figure.
Mistakes that throw off an estimate
The biggest is a missing slip. Forget a T4A or a bank interest slip and the estimate looks great until the assessment arrives. The second is credits. The estimate above counts a small set, and you may have more, such as medical costs or donations, so run the tax credits calculator. It covers federal credits only, not provincial ones.
A third is using last year’s withholding as if nothing changed. A raise, a second job or a mid-year move can shift the box 22 amount a lot, so use this year’s slips, not memory.
Deadlines matter too. For the 2025 return the CRA’s date was April 30, 2026, with June 15, 2026 for people with business income, though any balance was still due April 30. Dates for the 2026 return aren’t published yet, so we can’t give them. A late return owing tax costs 5% of the balance plus 1% for each full month, up to 12 months, on the 2025 return.
If your estimate keeps coming out as a large balance year after year, ask your employer to withhold more, or look at instalments.
Where the numbers come from
Brackets and credit amounts for 2026 come from the Canada Revenue Agency and the Ontario government tables in this site’s data files. The refund and RRSP examples are outputs of our own engine for one Ontario employee, with no other income. Filing dates and penalties come from the CRA pages for the 2025 return. This site has no link with the CRA, and your assessment is what counts.
Frequently asked questions
How do I estimate my tax refund?
Work out the tax on your income, then subtract the tax already withheld, which is in box 22 of your T4. Anything left over is your refund.
Will an RRSP contribution raise my refund?
Yes. The deduction lowers taxable income, and the saving follows your bracket. In our example $5,000 saved $1,632.50 on a $75,000 salary in Ontario.
Why is my actual refund different from an estimate?
Estimates count only basic credits, so extra claims, missing slips and benefit changes move the final figure.
When was the deadline for the 2025 return?
April 30, 2026 for most people, and June 15, 2026 for those with business income, though any balance was still due April 30.
Where do I find the tax already withheld?
In box 22 of your T4 for employment income. Add any instalments you paid during the year.
- How to file your tax return in Canada: steps and dates
What to gather, when your return is due and how to file in Canada, from the first slip to the notice of assessment that closes the year