Your refund is the tax withheld minus the tax you owe, nothing fancier. With $75,000 of pay and $14,000 withheld in Ontario, the calculator finds $12,705 of tax owed and a refund of $1,295. Type in the boxes from your T4 to try your own year.
Where do I find each number?
Most of it’s printed on your slips. Employment income is box 14 of the T4, and income tax withheld is box 22. Paid tax instalments during the year? Add them to the withheld amount. Deductions cover things like an RRSP contribution, child care costs and union dues, and other credit amounts take claims such as a spouse amount.
| Input | Where to find it |
|---|---|
| Employment income | T4, box 14 |
| Income tax withheld | T4, box 22, plus instalments |
| Other taxable income | Interest, rent, pensions |
| Deductions | RRSP receipts, child care, union dues |
| Province | Where you lived on 31 December |
Got more than one T4? Add the box 14 amounts together and do the same with box 22. People with two jobs are the ones most likely to be surprised in spring, since each employer withholds as if theirs were the only paycheque.
What do refunds look like in Ontario?
The default is $75,000 of pay with $14,000 withheld. Taxable income is $74,273, income tax is $12,704.65 and the refund is $1,295.35.
Lower the withholding to $10,000 and the same person owes $2,704.65. Employers deduct tax by formula, so if you changed jobs or had a second income partway through the year, the formula doesn’t know about it and you can land on the wrong side.
Now go back to the default and add a $5,000 RRSP deduction. Taxable income falls to $69,273, tax drops to $11,072.15 and the refund grows to $2,927.85. That’s $1,632.50 more than before, about a third of the contribution coming straight back.
One more to try. $60,000 of pay with $8,000 withheld gives tax of $8,320.50 and a balance of $320.50. That shortfall is small, and it would flip to a refund with a modest RRSP deduction.
Is a big refund good news?
Not really, and a balance isn’t bad news either. It’s tempting to treat a refund as a prize, but it’s your own money coming back late. A big refund means more tax was held back than your year needed. A balance owing means too little was. Both just settle the gap between what you’ve paid and what the rules require. Run the tool before you file, and again after each new slip that turns up in the mail or in your online account, so April doesn’t bring a surprise you couldn’t have seen coming.
Why might my real refund differ?
- Credits and benefits missing from the tool can raise a refund.
- Tuition, health costs and gifts to charity have no box of their own, so use the other credit amounts box or the tax deductions and credits calculator.
- A late T4 slip, a second employer or unreported interest can move the result.
- A rounding difference of a few bucks is normal. The CRA works from your slips and may reach a slightly different figure on your notice of assessment.
When is the balance due, and what if I owe?
A balance owing is due by 30 April, even if you file later. After that date the CRA charges daily compound interest on what’s still unpaid, starting the day after it was due, according to its page on line 48500, balance owing. Self-employed people get until 15 June to file, but the payment date stays 30 April.
If you expect a big one every year, the tax instalments calculator tells you if quarterly payments are needed. Curious what your next dollar of income costs? Try the marginal tax rate calculator. For the full yearly estimate, open the income tax calculator.
Where the numbers come from
Tax steps, the personal amount and the CPP and EI credits are 2026 figures from Canada.ca and each province, last checked on 29 September 2026. We aren’t connected to the CRA or any government body, and the result is an estimate, not an assessment.
About this calculator
- What it does
- Estimate your refund or balance owing from your income and the tax already withheld.
- Category
- Income Tax
- Last checked
- September 30, 2026
- Result type
- Estimate for information only, not tax advice.
Frequently asked questions
How do I work out my refund by hand?
Add the tax withheld and any instalments, then subtract your tax bill. A negative answer is a balance to pay.
Which slip shows the tax withheld?
Box 22 of your T4 shows income tax deducted. Add any instalments you paid during the year.
What does an RRSP deduction do to the result?
On $75,000 of pay in Ontario, a $5,000 deduction lifts the refund from $1,295 to $2,928.
When is a balance due?
By 30 April, as the calculator notes. Filing later doesn't move that date.
Why would my actual refund be different?
Credits and benefits the tool leaves out can raise it, and a late slip can change your income.
Sources and updates
Updated: . How we check rates · Editorial team · Updates