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An income tax refund estimator works out one thing: the tax you’ll owe for the year, minus what your employer already sent to the CRA. On an $80,000 salary in Ontario with $16,000 withheld, that gap 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 number you type in for tax paid.
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 2026 filing dates aren’t on a CRA page yet, so check the CRA’s important dates page before you plan around a day. 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 page doesn’t promise a number of days for an online return. It asks residents to wait 12 weeks before contacting it about a refund, and 16 weeks if you live outside Canada. In between, the progress tracker in My Account shows where the return sits. You can also phone the automated refund line.
Interest is a small bonus, and a rare one. For 2025 refunds the CRA says it pays compound daily interest in some cases, starting from the latest of three dates: 30 days after the balance due date, 30 days after you filed, or the day you overpaid. Don’t count on it.
Signing up for direct deposit 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.
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’s tax refunds page. This is an independent site, and no government body is behind it.
Frequently asked questions
How accurate is a refund estimate?
It's as accurate as the numbers you enter, mainly your income and tax withheld. Credits, carry-forwards and benefits you leave out will change the final figure.
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.
Can the CRA keep my refund?
Yes. Its refund page lists outstanding debts, garnishment orders and unpaid GST/HST returns as reasons.
How long should I wait before asking about my refund?
The CRA asks residents to wait 12 weeks. You can watch the progress tracker in My Account meanwhile.
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.
- 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