Updated Checked by the Tax-Services.ca editorial team How we check
If you live in Ontario, the CRA is the agency you deal with for both your federal and your Ontario income tax. You file one return, and form ON428 works out the provincial part. For the 2025 tax year, most people had to file and pay by 30 April 2026.
Who collects Ontario income tax?
You don’t send a second return to a provincial office. Your Ontario tax is calculated on form ON428 and reported on the same return as the federal tax. The CRA says you have to complete ON428 if you lived in Ontario at the end of the year.
Most Ontario credits follow the same eligibility rules as the federal ones. The amounts are different, though, so the same medical bill or tuition claim gives you a different credit federally and provincially. That’s normal, not a mistake in your software.
We can’t tell you where a CRA office is or which phone line to call. We didn’t confirm any of that, and those details change. Start from the CRA’s own Ontario page and your online account.
What does Ontario charge on top of federal tax?
Ontario has its own slabs, listed on the CRA’s 2026 rates page.
| Ontario taxable income | Rate |
|---|---|
| Up to $53,891 | 5.05% |
| $53,891 to $107,785 | 9.15% |
| $107,785 to $150,000 | 11.16% |
| $150,000 to $220,000 | 12.16% |
| Over $220,000 | 13.16% |
There’s also the Ontario Health Premium. The CRA says you pay it if you lived in Ontario at year end and your taxable income is over $20,000. It shows up on the same return as everything else.
Take $60,000 of taxable income and only the basic personal amount as a credit. Our engine gives about $6,193 of federal tax and $3,225 for Ontario, including the premium, so around $9,417 in all. Actual bills come out lower once you claim CPP, EI and other credits. The income tax calculator lets you try your own numbers.
When is the deadline to file?
For the 2025 return, the dates on the CRA page were these.
| Who | File by | Pay by |
|---|---|---|
| Most individuals | 30 April 2026 | 30 April 2026 |
| Self-employed, or spouse of one | 15 June 2026 | 30 April 2026 |
Those dates are behind us now. The 2026 return dates aren’t published on the pages we checked, and guessing them would be a mistake, since a weekend can move a date and the CRA sets it. Check the CRA due dates page in the new year.
Self-employed people trip on one thing more than any other. The later filing date doesn’t move the payment date, so if you owe, you still have to pay by 30 April to avoid interest. If that’s you, the tax instalments calculator tells you if you need to pay during the year, and the self-employed tax calculator gives a first estimate.
How do you check what the CRA owes you or you owe it?
Your notice of assessment is the answer to both questions. It shows the refund or balance and your RRSP room. If your number and the CRA’s don’t match, check your slips first, because a slip you forgot to enter is the easy thing to miss and the CRA gets its own copy.
If you’d like a rough answer before you file, the tax refund calculator compares your income tax with what your employer already withheld. Small differences are normal, but a large one deserves a second look at your slips, your credits and the province you entered, since one wrong field can move a refund by hundreds of dollars.
Mistakes that catch Ontario filers
Many Ontario filers assume there’s a provincial agency to talk to. There isn’t one for income tax, so questions about ON428 go to the CRA.
Another slip is copying a rate table from an old year. Limits move every January. Also, our Ontario marginal rate reading looks very high near $200,000, and we haven’t confirmed why, so don’t rely on that one figure.
Where the numbers come from
Rates and slabs are from the Canada Revenue Agency’s 2026 rates page. The health premium and ON428 wording come from the CRA’s Ontario tax pages. Deadlines come from the CRA’s filing dates page for the 2025 return. We checked them on 30 September 2026. We aren’t connected to the CRA or the Ontario government.
Frequently asked questions
Do I file a separate Ontario tax return?
No. Ontario tax is worked out on form ON428 and reported on your one federal return to the CRA.
Who pays the Ontario Health Premium?
The CRA says you pay it if you lived in Ontario at year end and your taxable income is over $20,000.
What was the 2025 filing deadline?
30 April 2026 for most people, and 15 June 2026 for self-employed people. Any tax owing was still due 30 April.
What is the 2026 return deadline?
We couldn't find it published yet. Check the CRA due dates page before you rely on a date.
What is Ontario's lowest tax rate?
5.05% on the first $53,891 of taxable income in 2026.
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Information only. This page is general information, not tax, legal or accounting advice. Tax-Services.ca is an independent publisher: we don't prepare or file tax returns or offer tax services, and we have no connection with the CRA, Revenu Québec, any government or any company named on this page. Check the figures that matter with an official source or a qualified professional.