Which CRA deadlines apply to your business depends on how it is structured — sole proprietor or corporation, GST/HST registrant or not, employer or not — and in several cases on your fiscal year-end, your reporting period, or how much payroll you remit. This guide collects the deadlines Ontario small businesses ask us about most, verified against the Canada Revenue Agency’s own pages in September 2026. Fixed calendar dates come first; the deadlines that depend on your circumstances are explained separately, because those are the ones that catch business owners out.
Still ahead in 2026 (and the first dates of 2027)
| Date | Who it applies to | What is due |
|---|---|---|
| September 15, 2026 | Individuals who pay income tax by instalments | Third 2026 instalment |
| October 15, 2026 | Quarterly payroll remitters | Source deductions for July–September |
| December 15, 2026 | Individuals who pay by instalments | Fourth and final 2026 instalment |
| December 31, 2026 | Farmers and fishers who pay by instalments | Single annual instalment |
| January 15, 2027 | Quarterly payroll remitters | Source deductions for October–December |
| March 1, 2027 | Employers and corporations that paid salaries, fees or dividends in 2026 | T4, T4A and T5 information returns — the usual “last day of February” (February 28, 2027) falls on a Sunday, so returns received by Monday, March 1, 2027 are on time |
| April 30, 2027 | All individuals, including the self-employed | 2026 T1 balance owing; T1 filing deadline for most individuals |
| June 15, 2027 | Self-employed individuals and their spouses | 2026 T1 filing deadline (payment was still due April 30) |
Monthly and quarterly GST/HST returns, monthly payroll remittances, and every corporate deadline continue on their own clocks — those rules are below.
Self-employed? Your T1 has two different deadlines
If you or your spouse or common-law partner ran a business during the year, the CRA gives you until June 15 of the following year to file your T1 return. The trap is that any balance owing is still due April 30 — interest starts on May 1 even though your return is not late. For the 2026 tax year, that means payment by April 30, 2027 and filing by June 15, 2027. (One narrow exception: if your business expenditures are mainly tax-shelter investments, the June 15 extension does not apply.)
Practical consequence: your books need to be current enough by mid-April to estimate what you owe. If they are behind, that is exactly what our catch-up bookkeeping service exists for, and our self-employed bookkeeping packages keep the estimate ready year-round.
Corporations: T2 deadlines depend on your year-end
A corporation’s T2 return is due six months after its fiscal year-end — there is no single calendar date. A December 31 year-end files by June 30; a June 30 year-end files by December 31.
Payment runs on a faster clock than filing: the balance of corporate tax is generally due two months after year-end. Many small Ontario corporations get three months instead — but only if the corporation was a Canadian-controlled private corporation (CCPC) throughout the year, claimed the small business deduction for this or the previous year, and (together with any associated corporations) stayed under the business limit in the prior year. If you are not sure which rule applies to your corporation, that is a question worth settling before year-end, not after — see our corporate tax (T2) and year-end services.
GST/HST: your reporting period sets the deadline
| Reporting period | Filing deadline | Payment deadline |
|---|---|---|
| Monthly | One month after the end of the period | Same day as filing |
| Quarterly | One month after the end of the quarter | Same day as filing |
| Annual (most) | Three months after fiscal year-end | Same day as filing |
| Annual — individual with a December 31 year-end and business income | June 15 | April 30 |
The last row mirrors the T1 pattern: a self-employed annual filer gets the June 15 filing date, but the CRA still expects the net tax by April 30. Tracking HST accurately through the year — not reconstructing it at the deadline — is a core part of our HST filing service.
Payroll remittances: your remitter type sets the schedule
Source deductions (income tax, CPP, EI) follow a schedule based on your average monthly withholding amount (AMWA) from two calendar years ago:
| Remitter type | Threshold | Remittance due |
|---|---|---|
| Regular | AMWA under $25,000 | 15th of the month after the month you withheld |
| Quarterly — new small employer | Monthly withholding under $1,000 with a clean compliance record | April 15, July 15, October 15, January 15 |
| Quarterly — established | AMWA under $3,000 two years ago | April 15, July 15, October 15, January 15 |
| Accelerated — Threshold 1 | AMWA $25,000–$99,999 | Pay dates 1st–15th: the 25th of the same month; pay dates 16th–month-end: the 10th of the next month |
| Accelerated — Threshold 2 | AMWA $100,000+ | Third working day after the 7th, 14th, 21st and last day of the month |
Most new Ontario small businesses are regular remitters: withhold in September, remit by October 15. Late payroll remittances draw some of the CRA’s steepest penalties, which is why remittance tracking is built into our payroll service.
Instalments
Individuals (including the self-employed) who owe enough tax to be in the instalment system pay on March 15, June 15, September 15 and December 15; farmers and fishers pay once, on December 31. Corporations generally pay monthly instalments starting one month less a day after the tax year begins; small CCPCs meeting the CRA’s income, capital and compliance tests may pay quarterly instead. Corporate instalment dates therefore depend on your year-end, not the calendar.
Information returns: T4, T5 — and the T5018 exception
T4 and T4A slips (salaries and fees) and T5 slips (dividends, interest) are due on or before the last day of February following the calendar year they cover. One exception matters to our construction clients: the T5018 return of payments to subcontractors is due six months after the end of the reporting period you chose (calendar year or fiscal year) — it does not follow the February rule.
The weekend and holiday rule
When a due date lands on a Saturday, Sunday or a public holiday the CRA recognizes, your return is on time if the CRA receives it — or it is postmarked — on or before the next business day. For payments the standard is stricter: the CRA must receive the payment by the next business day; a postmark is not enough. That is why the February 28, 2027 slip deadline effectively becomes Monday, March 1, 2027.
FAQ
My corporation’s year-end is June 30. When are my T2 and my balance due?
File the T2 by December 31. Pay the balance by August 31 — or by September 30 if your corporation qualifies for the three-month CCPC rule described above.
What is the difference between the filing deadline and the payment deadline?
They are separate obligations. Filing late triggers a late-filing penalty on any balance owing; paying late triggers arrears interest even if the return itself is on time. The self-employed June 15 / April 30 split is the clearest example: the return can wait until June, the money cannot.
I’ve already missed a deadline. What should I do?
File as soon as possible — penalties and interest grow with time, and repeated late filing increases them. If the real blocker is that the books behind the return aren’t done, start there: our catch-up bookkeeping service rebuilds behind books to filing-ready, and tax preparation is done from the same reconciled records. Fixed monthly pricing is published for both.
Sources and a note on this guide
Every deadline above was checked in September 2026 against the CRA’s own pages: T1 filing due dates, T2 filing deadlines, corporate balance-due day, GST/HST deadlines, payroll remittance due dates, individual instalments and information-return due dates. Deadlines can change; the CRA pages are always the authority.
This guide is general information for Ontario small businesses, not tax or legal advice. Your corporation’s year-end, remitter classification and instalment position change which rules apply — confirm your own dates with the CRA or a qualified professional before relying on them.
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