1. Q1 — January to March
The quiet quarter. Everyone's still settling year-end numbers, so the big dates here are slip filings and the RRSP cutoff for last year's return.
| Date | What's due | Who this is for |
|---|---|---|
| Jan 15 | December 2025 payroll remittance (regular remitter) | Employers on monthly remittance |
| Feb 2 (Jan 31 Sat) | Q4 2025 HST return and payment (quarterly filers) | HST-registered businesses on quarterly |
| Feb 17 (Feb 15 Sun) | January payroll remittance | Employers on monthly remittance |
| Mar 2 (Feb 28 Sat) | T4, T4A, T5 slips filed with CRA and sent to recipients | Employers and payers of investment income |
| Mar 2 (Mar 1 Sun) | RRSP contribution deadline for the 2025 tax year | Individuals with RRSP room |
| Mar 16 (Mar 15 Sun) | First personal tax instalment for 2026 | Individuals CRA has asked to pay instalments |
| Mar 16 (Mar 15 Sun) | Ontario EHT 2025 annual return (if payroll above the exemption) | Ontario employers over the EHT threshold |
| Mar 16 (Mar 15 Sun) | February payroll remittance | Employers on monthly remittance |
| Mar 31 | T5013 partnership information return (Dec 31 year-end) | Partnerships with a calendar year-end |
2. Q2 — April to June
The busiest quarter of the year. April 30 is the one most people know, but self-employed filers have a June 15 filing deadline that does not extend the balance owing — interest starts May 1.
| Date | What's due | Who this is for |
|---|---|---|
| Apr 15 | March payroll remittance | Employers on monthly remittance |
| Apr 30 | T1 personal tax return filed | Most individuals (non-self-employed) |
| Apr 30 | T1 balance owing paid | All individuals, including self-employed |
| Apr 30 | Q1 2026 HST return and payment (quarterly filers) | HST-registered businesses on quarterly |
| Apr 30 | Underused Housing Tax (UHT) return for 2025 | Owners of vacant or underused residential property subject to UHT |
| May 15 | April payroll remittance | Employers on monthly remittance |
| Jun 15 | T1 personal tax return filed (self-employed) | Self-employed filers and their spouses |
| Jun 15 | Second personal tax instalment for 2026 | Individuals CRA has asked to pay instalments |
| Jun 15 | May payroll remittance | Employers on monthly remittance |
3. Q3 — July to September
A calmer quarter. Two payroll remittances, a quarterly HST filing, and a personal instalment. Good time to get the books caught up.
| Date | What's due | Who this is for |
|---|---|---|
| Jul 15 | June payroll remittance | Employers on monthly remittance |
| Jul 31 | Q2 2026 HST return and payment (quarterly filers) | HST-registered businesses on quarterly |
| Aug 17 (Aug 15 Sat) | July payroll remittance | Employers on monthly remittance |
| Sep 15 | Third personal tax instalment for 2026 | Individuals CRA has asked to pay instalments |
| Sep 15 | August payroll remittance | Employers on monthly remittance |
4. Q4 — October to December
The year-end quarter. One more HST filing, one more personal instalment, and the calendar year closes. If you're on a December 31 fiscal year-end, the clock for your next T2 starts on January 1.
| Date | What's due | Who this is for |
|---|---|---|
| Oct 15 | September payroll remittance | Employers on monthly remittance |
| Nov 2 (Oct 31 Sat) | Q3 2026 HST return and payment (quarterly filers) | HST-registered businesses on quarterly |
| Nov 16 (Nov 15 Sun) | October payroll remittance | Employers on monthly remittance |
| Dec 15 | Fourth personal tax instalment for 2026 | Individuals CRA has asked to pay instalments |
| Dec 15 | November payroll remittance | Employers on monthly remittance |
| Dec 31 | Fiscal year-end for calendar-year corporations and individuals | Most corporations, all individuals |
5. Dates that depend on your year-end
Corporate tax and a few other filings don't land on fixed calendar dates — they move with your fiscal year-end. Here are the rules.
| Filing | When it's due | Who this is for |
|---|---|---|
| T2 corporate return | Six months after the fiscal year-end | All Canadian corporations |
| T2 balance owing (CCPC, SBD) | Three months after the fiscal year-end | CCPCs claiming the small business deduction |
| T2 balance owing (other) | Two months after the fiscal year-end | Corporations not claiming the SBD |
| Corporate tax instalments | Last day of each month or quarter, depending on the corporation's schedule | Most corporations with tax owing above $3,000 |
| T5018 contractor slips | Six months after the fiscal year-end, or by the last day of February on a calendar-year basis | Businesses in the construction industry paying subcontractors |
| HST return (annual filer, corporate) | Three months after the fiscal year-end | Annual-filer corporations |
| HST return (annual filer, individual) | June 15 filing, April 30 payment | Sole proprietors with a December 31 year-end |
| T3 trust return | 90 days after the trust year-end | Trusts required to file |
| Payroll remittance (accelerated) | Twice a month or weekly, depending on your average monthly withholdings | Employers above CRA's accelerated thresholds |
Not sure which rules apply to you? The payroll guide walks through remittance thresholds, and the tax preparation guide covers T1 and T2 in full.
6. When a deadline falls on a weekend or holiday
CRA policy: when a statutory deadline lands on a Saturday, Sunday, or federal public holiday, CRA considers your return or payment on time if it's received by the next business day.
That's why the 2026 tables above show some dates shifted in the small grey note beside them. For example, February 28, 2026 is a Saturday, so slips don't have to be filed until Monday, March 2. The rule applies to electronic payments and returns as well as paper mail.
One warning: the next-business-day rule does not delay the start of interest. If you owe money on your T1 and don't pay it by April 30, interest starts May 1 regardless of what day of the week May 1 falls on. File on time and pay on time if you want to keep the meter off.
7. The three dates most owners miss
In almost 30 years of filing for Ontario small business owners, three deadlines trip people up more than all the others combined.
The June 15 self-employed trap
The June 15 filing deadline only extends the filing date for self-employed filers and their spouses. Interest on any balance owing starts May 1. So if you're self-employed and you owe money, file and pay by April 30 anyway — the extra six weeks are only useful if your numbers work out to a refund.
The RRSP 60-day rule
RRSP contributions made in the first 60 days of the year can be deducted on either last year's return or this year's — your choice. For 2025 returns, that's contributions up to March 2, 2026. A lot of owners think the deadline is December 31 and miss two months of contribution room that would have reduced last year's tax bill.
The T2 balance owing trap
Your T2 return is due six months after year-end. Your T2 balance is due three months after year-end (two for non-SBD corporations). Miss that earlier date and interest starts compounding even though you still have three months to file the return. It catches first-year incorporators every spring.
We track these for every client.
If you're not sure which of these deadlines apply to your situation, or which ones you've been missing, book a free review. We go through your setup, figure out which dates you actually need to hit, and hand you a one-page schedule.
Book a Free Review