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An income tax refund estimator subtracts the tax you owe for the year from what your employer already sent the CRA. On an $80,000 salary in Ontario with $16,000 withheld, that is a refund of $1,872.15. Change the withholding and it flips into a bill, so the estimate is only as good as the tax paid you type in.
Start with the tax refund calculator. You need your pay, the tax withheld so far (it’s on your last pay stub, year to date, or box 22 of your T4 once it arrives) and any deductions such as an RRSP contribution.
How does the estimate work?
There’s no mystery in it. The tool adds up your income, subtracts deductions, applies the federal and provincial brackets, takes off your credits, and compares the result with tax already paid. If you paid more than you owe, you get money back. If you paid less, you owe the difference.
It uses 2026 rates, so it fits the return you’ll file in spring 2027. The CRA has not posted a due dates page for the 2026 return yet, but its own tip for newcomers uses April 30, 2027. The self-employed usually get until June 15, with any balance still due April 30. For the 2025 return, the date was 30 April 2026.
Withholding is where people go wrong. Your employer takes tax off each paycheque using a schedule, not your actual year, so a second job, a raise late in the year or a big bonus can leave you short. Tax on $80,000 of pay in Ontario comes to $14,127.85 at 2026 rates. Withhold $13,500 and you owe $627.85 in April instead of getting a cheque.
What moves a refund up or down?
Deductions do the most. They come off your income before the brackets apply, so each dollar is worth your top rate. Here’s the same $80,000 Ontario salary with $16,000 withheld and different RRSP contributions.
| Deduction | Tax for the year | Refund |
|---|---|---|
| None | $14,127.85 | $1,872.15 |
| $3,000 | $13,238.35 | $2,761.65 |
| $8,000 | $11,605.85 | $4,394.15 |
Every figure above came from the site’s own maths, with CPP and EI credits included. Nothing else was claimed, no medical costs, no donations, no tuition. Notice the pattern: the first $3,000 saves $889.50 and the next $5,000 saves $1,632.50, so a bigger deduction keeps paying at roughly the same rate here.
Credits work differently. Most of them shave a fixed amount off your tax, and you claim them when you file. The tax credits calculator covers the federal ones, so run it if you have a spouse amount, a disability amount or medical costs.
Why is my real refund different from the estimate?
Usually because something wasn’t in the box. The refund tool takes employment income, other income, deductions and a lump of extra credits. It has no field for a T5 with dividends taxed differently, or for benefits that get clawed back. It also doesn’t know about carry-forward amounts from past years.
The CRA can also keep some or all of a refund. Its tax refunds page lists amounts owing, garnishment orders, certain outstanding federal, provincial or territorial debts and unpaid GST/HST returns from a sole proprietorship or partnership. A refund of $2 or less is on that list too.
And the estimate stops at your tax bill. It doesn’t include the GST/HST credit or the child benefit, which the CRA pays separately. If you have kids, run the child benefit calculator on its own and don’t add the result to your refund.
One more cause is a late slip. A T4A or an investment slip that shows up in March can move the answer by a few hundred dollars, so it’s worth waiting for the full pile before you trust the number.
How long until the money shows up?
The CRA’s tax refunds page says it processes electronic returns within 2 weeks and returns from non-residents within 16 weeks, as long as it received the return on or before the due date. It gives no fixed time for a paper return on that page, and its contact page has said 12 weeks. If your refund hasn’t arrived in the stated time, check My Account first, where the return tracker shows where it sits, or phone the automated refund line. Our guide to how long a refund takes and why and the CRA refund timelines page go through the usual delays.
Interest is a small bonus, and a rare one. For 2025 refunds the CRA says it may pay compound daily interest, starting from the latest of three dates: May 30, 2026, the 30th day after you filed, or the day you overpaid. The CRA had not published the 2026 dates when we checked. Don’t count on interest.
The CRA deposits a refund into the bank account it has on file, and sends a cheque only if direct deposit isn’t set up before you file. Signing up is the easiest way to avoid a cheque stuck in the mail.
Is a big refund a good thing?
Not really. A refund is your own money that sat with the CRA all year, interest-free. Mind you, plenty of people like it as forced savings, and that’s fine. If you’d rather have the cash in each paycheque, a smaller refund is the goal, and you can aim for it by adjusting what your employer withholds.
What if the estimate says I owe money?
Then you have until the filing deadline to pay, but sooner is kinder to your wallet. Ask your employer to withhold more, or see if instalments apply, which the tax instalments calculator models. For the whole picture of pay, tax and take-home, the income tax calculator shows federal and provincial tax side by side. For a walk through the filing steps, see our guide to filing taxes in Canada.
What mistakes make a refund estimate wrong?
- Typing the wrong withholding. Use box 22 of the T4 or the year-to-date income tax line on your latest pay stub, and not the CPP or EI line.
- Forgetting a second job or side income. Tax is usually not withheld on side income, so it raises the bill.
- Leaving out deductions you have receipts for, such as RRSP contributions. The RRSP calculator shows what a contribution does to the tax.
- Adding the GST/HST credit or the child benefit to the refund. They are paid separately.
- Trusting the number before every slip has arrived. Use CRA My Account to see slips as they are filed.
When the estimate looks right, the step-by-step guide to filing your tax return in Canada covers what comes next.
How do tax brackets and deductions change a refund estimate?
An estimate runs your income through the federal income tax brackets, which run from 14% to 33% in 2026, and then through your province's brackets, which in Ontario run from 5.05% to 13.16%. Tax on $80,000 of pay in Ontario comes to $14,127.85 at those rates. A refund is whatever the CRA already holds above that figure, so a higher withholding gives a larger refund and a lower one gives a balance owing.
Deductions change the tax before the brackets are applied. In the table above, a $3,000 RRSP deduction lifts the refund from $1,872.15 to $2,761.65, and an $8,000 deduction lifts it to $4,394.15. If you want to see the federal brackets themselves, the federal tax rates guide explains how they work.
Where the figures come from
Tax rates and credit amounts are the 2026 federal and provincial figures used across this site, taken from CRA and provincial finance pages. The refund timing, the reasons for withholding a refund and the interest rule come from the CRA tax refunds page, which we read in November 2026. This is an independent site, and no government body is behind it.
Frequently asked questions
How accurate is a refund estimate?
It is only as accurate as the numbers you enter, mainly your income and the tax withheld. Credits, carry-forward amounts and benefits that you leave out will change the final figure, and a late slip can move it by a few hundred dollars.
Where do I find the tax already withheld?
Look at box 22 of your T4, or the year-to-date income tax line on your latest pay stub. Do not use the CPP or EI lines, because those are separate deductions that only feed the credits in the estimate. It shows the tax your employer has already sent to the CRA.
How long should I wait before asking about my refund?
The CRA says it processes electronic returns within 2 weeks when they arrive by the due date, and within 16 weeks for non-residents. If the time has passed, check the tracker in My Account before you phone. Do not phone before the stated time has passed.
Does an RRSP contribution raise my refund?
It lowers your taxable income, so tax drops. On $80,000 in Ontario, a $3,000 deduction adds $889.50 to the refund, and an $8,000 deduction adds $2,522, which is $4,394.15 minus the original $1,872.15. The RRSP calculator shows the longer view.
Can the CRA keep my refund?
Yes. The CRA says it may keep a refund to cover an amount you owe, a garnishment order, certain federal, provincial or territorial debts and unpaid GST/HST or payroll returns from a sole proprietorship or partnership. It also does not pay a refund of $2 or less.
What if the estimate says I owe money?
The balance is due on the same date as the filing deadline for most people, April 30. Ask your employer to withhold more, or check whether instalments apply. Interest starts the day after the due date. The tax instalments calculator can model the payments.
- 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