For many Ontario business owners, the hardest part of tax season isn't the math. It's keeping track of the dates. The CRA sets different deadlines for filing and for paying, and they depend on whether you're a sole proprietor or a corporation, and whether you're registered for GST/HST.
Here's a plain-language guide to the main ones.
Sole proprietors: two dates, not one
If you report business income on your personal (T1) return, you have two separate deadlines:
Filing: June 15. Self-employed individuals, and their spouses or common-law partners, have until June 15 to file. For 2026 income, that's June 15, 2027.
Payment: April 30. Any balance owing is still due April 30. For 2026 taxes, that's April 30, 2027.
This is where many owners get caught. The later filing date doesn't push back the payment date, and the CRA charges daily compound interest on unpaid balances starting the day after they're due. Aim to have your books closed by early April so you can estimate what you owe and pay on time.
Instalments
No tax is withheld from self-employment income, so you may have to pay instalments during the year. For 2026, you generally must pay instalments if your net tax owing is more than $3,000 in 2026 and was also more than $3,000 in either 2025 or 2024 (Quebec uses a different threshold).
Instalments are due March 15, June 15, September 15 and December 15. The next one is December 15, 2026. The CRA sends reminders to people who will likely need to pay.
Corporations: six months to file, less time to pay
T2 filing deadline
A corporation must file its T2 return within six months of its tax year-end. When the year ends on the last day of a month, the return is due by the last day of the sixth month after. The CRA's own example: a March 31 year-end means a September 30 filing deadline.
Balance-due day
The tax itself is due much sooner than the return:
Generally, two months after the end of the tax year.
Three months for a Canadian-controlled private corporation (CCPC) that was a CCPC all year, claimed the small business deduction for the current or previous year, and whose previous-year taxable income (or its associated group's) didn't exceed its business limit.
Many corporations also pay monthly or quarterly instalments, and eligible small CCPCs can pay quarterly. Check your schedule in My Business Account.
GST/HST return deadlines
If you're registered, you must file a return for every reporting period, even with no sales (a "nil return"). Most registrants must file electronically.
Monthly or quarterly filers: file and pay 1 month after the period ends (for example, a quarter ending March 31 is due April 30).
Annual filers (most businesses): file and pay 3 months after your fiscal year-end.
Annual filers who are sole proprietors with a December 31 year-end and business income: pay by April 30, file by June 15.
Annual filers may also owe GST/HST instalments, due within one month after each fiscal quarter.
Payroll remittances
If you have employees, the source deductions you withhold are due based on your remitter type:
Regular remitters pay by the 15th of the following month.
Quarterly remitters (eligible small employers with a perfect compliance record) pay by April 15, July 15, October 15 and January 15.
Larger "accelerated" remitters pay more often.
T4 information returns are due by the last day of February. Late remittances can carry penalties of 3% to 10% (up to 20% for repeated, knowing failures), plus interest.
Weekends and holidays
If a due date falls on a Saturday, Sunday or CRA-recognized public holiday, you're on time if the CRA receives it, or it's postmarked, by the next business day.
How to stay ahead of every deadline
Deadlines are far easier to meet when your records are current all year:
Reconcile bank and credit card accounts monthly.
Track GST/HST collected and paid as you go.
Keep receipts and invoices organised and stored securely.
Put every CRA filing and payment date in one calendar.
Curious where bookkeeping fits in? Read what a bookkeeper does, or see how our bookkeeping services keep records ready for tax time.
Frequently asked questions
When are small business taxes due in Canada?
Sole proprietors pay any balance by April 30 and file by June 15. Corporations file within six months of year-end but generally pay within two months (three for eligible CCPCs).
Is June 15 also the payment deadline?
No. It's only the filing deadline for self-employed individuals. Tax owing is due April 30.
Do I file a GST/HST return if I had no sales?
Yes. Registrants file for every reporting period, even if it's a nil return.
What if a deadline falls on a weekend?
It moves to the next business day.
Get your records ready before the deadlines hit
Oakridge Business Services helps small business owners across Ontario keep their books accurate, current and ready for tax time, so deadlines feel routine instead of stressful. Book a free consultation and we'll look at where your records stand today.
This article is general information, not tax advice for your situation.
