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Small business tax filing has two clocks. If you run the business yourself as a sole proprietor, your return is due June 15 but any tax you owe is due April 30. A corporation files its T2 return within six months of its year end and usually pays sooner than that.
Which return do you file, and when?
The answer turns on how the business is set up, and size has nothing to do with it. A sole proprietor reports business income on the personal return, using form T2125 for the business part. A corporation is a separate taxpayer with its own return. Ask yourself one thing first: are you taxed personally or through a company?
| Business type | Return | Filing deadline | Payment deadline |
|---|---|---|---|
| Sole proprietor | T1 with form T2125 | June 15 (December year end) | April 30 |
| Corporation | T2 | 6 months after year end | 2 months after year end, 3 for some CCPCs |
The 2026 dates in that table apply to the 2025 tax year. For the next one, check the CRA’s dates page before you plan around it, because we couldn’t find the 2027 dates printed yet. Weekends and holidays can also shift a deadline.
What does a sole proprietor pay on $80,000?
Say your business nets $80,000 in Ontario. The self-employed tax calculator shows $13,233.57 of federal and Ontario income tax, plus $8,892.90 of CPP, because you pay both halves. That’s $22,126.47, or 27.7% of the profit, and you keep $57,873.53.
Now drop the profit to $70,000 by claiming another $10,000 of real expenses. The total falls to $18,298.32. The extra expenses saved $3,828.15. That’s why receipts matter.
The tool leaves out EI, GST/HST and the expenses themselves, so it starts from profit after costs, which means you still need decent books before the number means anything. Treat it as a rough guide.
How does small business tax filing change once you incorporate?
You now file the T2, and the company pays tax on its profit. For a Canadian-controlled private corporation (CCPC) the federal small business rate is 9% on the first $500,000 of active business income. Ontario’s small business rate was cut on 1 July 2026, so a calendar 2026 year gets a blended rate, and 2027 should be lower. That blend is our estimate, not a published figure.
The corporate tax calculator gives $35,088 on $300,000 of Ontario profit, which is 11.7%. Above $500,000 the combined rate in the tool is 26.5%. It ignores taxable capital, passive income and associated companies that share the limit. A group of related companies can pay more than the figure shown, and a company with a lot of investment income can lose part of the low rate.
Pulling money out for yourself is taxed again. That part isn’t in the corporate figure, and the dividend tax calculator covers it.
What else has a date attached?
Filing isn’t the only deadline. If you owe a fair amount each year, the CRA expects instalments through the year. The tax instalments calculator splits a bill into four payments, for example four of $2,000 on $8,000 owing. If you have staff, you also remit CPP, EI and tax withheld, and the payroll remittance calculator gives the amounts per pay period.
GST/HST has its own filing schedule once you’re registered. We couldn’t confirm the registration threshold from a CRA page, so read that page before you decide you don’t need to register.
Where do owners slip up?
- Waiting until June 15 to pay. The filing date moved, the payment date didn’t, so interest starts in May.
- Mixing personal and business spending in one account, then not being able to prove a deduction.
- Treating the corporation’s tax as the whole bill and forgetting the tax on what you take out.
- Filing late with a balance owing, which adds a penalty on top of interest.
- Assuming a December year end. A corporation can choose another one, and its dates move with it.
Where the numbers come from
Deadlines come from Canada Revenue Agency pages on 2026 business tax deadlines and on when to file a corporation return, read in September 2026. The federal small business rate and $500,000 limit come from the CRA’s corporation tax rates page and the T2 guide, and provincial rates from CRA provincial pages. Personal figures use 2026 federal and Ontario schedules. This site has no link with the CRA or any government.
Frequently asked questions
When is small business tax filing due for a sole proprietor?
The return is due June 15 if you or your spouse is self-employed. Any tax owing is still due April 30.
When does a corporation file its tax return?
The T2 is due six months after the tax year ends. The balance is generally due two months after year end, or three for eligible CCPCs.
What form reports self-employed income?
Business income goes on form T2125, which attaches to your personal T1 return.
How much tax is that on $80,000 of profit in Ontario?
The calculator shows $13,233.57 of income tax and $8,892.90 of CPP, $22,126.47 in all.
What's the federal small business rate for a corporation?
It's 9% on the first $500,000 of active business income for a CCPC, before the provincial rate is added.
- Self-employed taxes in Canada: income, CPP and GST
How tax works when you are self-employed in Canada: reporting income and expenses, paying both halves of CPP, instalments and when to register for GST
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.