HST Filing Deadlines for Ontario Small Businesses (2026 Tax Year)

Your HST deadline is not one date. If you file monthly or quarterly, your return and your payment are both due one month after the reporting period ends. If you file annually, they are due three months after your fiscal year end, unless you are a sole proprietor with a December 31 year end, in which case your payment is due April 30 and your return is due June 15. Which one applies to you depends on a reporting period the CRA assigned when you registered.

How does the CRA decide how often I file HST?

The CRA assigns your reporting period based on your annual taxable supplies. You do not pick it at registration, though you can change it later.

Charities are assigned an annual period regardless of revenue (CRA: make changes to your GST/HST account, rule current for the 2026 tax year, accessed September 22, 2026). Most Guelph small businesses sit in the first row and file annually by default.

When are HST returns due in 2026?

Monthly and quarterly filers get the same rule: the return and the payment are both due one month after the end of the reporting period (CRA: reporting requirements and deadlines, rule current for the 2026 tax year, accessed September 22, 2026). Two of this year's quarterly dates land on a weekend, so the real deadline moves.

The shift comes from a CRA rule that applies to every filing frequency: if your due date falls on a Saturday, Sunday or public holiday recognized by the CRA, your return or payment counts as on time if the CRA receives it on the next business day (same CRA page as above). No CRA-recognized holiday lands on any of those Mondays.

Annual filers do not use this calendar. Your date keys off your own fiscal year end, three months after it, so a June 30 year end means a September 30 deadline.

Why is my HST payment due April 30 when my return is not due until June 15?

This one catches unincorporated owners every year. If you are an annual filer, a sole proprietor with a December 31 fiscal year end, and you had business income that year, your payment deadline is April 30 and your filing deadline is June 15 (same CRA page as above). The two dates are not interchangeable.

The practical effect: you need to know what you owe by April 30, so your books have to be finished by then even though the return can wait six more weeks. Owners who treat June 15 as the only date pay on time in their own minds and accrue interest in the CRA's records.

Do I have to pay HST in instalments?

If you are an annual filer and your net tax for the previous fiscal year was $3,000 or more, you may have to make quarterly instalment payments during the current fiscal year (CRA: find out if you need to pay GST/HST by instalments, rule current for the 2026 tax year, accessed September 22, 2026). Those instalments are due within one month after the end of each of your fiscal quarters (CRA: remit the GST/HST by instalments, accessed September 22, 2026).

So an annual filer can still make four payments a year. If that is you, electing to file quarterly often makes cash flow easier to read, because the payment and the return line up. You can change your reporting period through the File an election service in My Business Account or with Form GST20. Our guide to quarterly versus annual HST filing works through that trade-off.

What does it cost to file or pay HST late?

Filing late and paying late are two separate problems with two separate costs.

The late-filing penalty is calculated as A + (B x C), where A is 1% of the amount owing, B is 25% of A, and C is the number of complete months the return is overdue, to a maximum of 12 months. The CRA does not charge this penalty when you have $0 owing or when it owes you a refund. If you are required to file electronically and do not, the penalty is $100 for the first return and $250 for each one after that (CRA: GST/HST filing penalties, rules current for the 2026 tax year, accessed September 22, 2026).

Interest is separate and it does not care whether you filed. It starts accumulating on your debt from the day your payment was due, at a prescribed rate the CRA sets every quarter (CRA: interest and penalties on late or incorrect payments, accessed September 22, 2026). Look up the current quarter's prescribed rates on the CRA site. We do not print the rate here because it changes four times a year, and a stale number is worse than no number.

That split is the part owners get wrong. Submitting the return on time does not stop the interest clock. Only paying does.

What actually prevents a scrambled HST filing?

Almost every late or panicked HST return traces back to the same root cause. The books were not reconciled during the period, so nobody knew what was owed until the deadline was already close. Filing HST accurately is a bookkeeping problem wearing a tax deadline. Reconcile every month and you know your HST position all year, not just when a due date forces you to look.

That is the point of Intersect's monthly bookkeeping and HST/GST filing services. Books and Payroll starts at $1,500 a month and covers the bookkeeping, the reconciliation and the remittances, so the filing itself becomes a formality. For the wider picture, see what bookkeeping services in Guelph include and cost, and if you run payroll, the CRA payroll remittance deadlines run on their own separate schedule.

Behind on a filing already, or not sure which reporting period you are on? Get in touch and we will look at it with you.

Frequently asked questions

When is the HST deadline for quarterly filers in October 2026?

The July to September 2026 quarter ends September 30, so the return and payment are due October 31, 2026. That is a Saturday, and the CRA treats a return or payment received on Monday, November 2, 2026 as on time.

Is the HST filing deadline the same as the payment deadline?

For monthly and quarterly filers, yes. Both fall one month after the reporting period ends. For an annual filer who is a sole proprietor with a December 31 year end, the dates split: payment April 30, return June 15.

What happens if I file my HST return late but owe nothing?

The CRA does not charge a late-filing penalty when you have $0 owing or when it owes you a refund. File anyway, because an unfiled return holds up refunds and stalls other CRA processes.

Can I change how often I file HST?

Yes. A business assigned an annual or quarterly reporting period can elect to file more often, through the File an election service in My Business Account or Form GST20.