The self-employed tax deadline is June 15 — but your money is due April 30

The direct answer

If you're self-employed, your T1 return is due June 15, 2026, not April 30. But that's only a filing extension — your balance owing was still due April 30, 2026, and the CRA has been charging daily compound interest on any unpaid amount since May 1. The six-week gap between the two dates is where self-employed filers quietly lose money every year.

Who actually gets the June 15 deadline

The extended deadline applies if you were self-employed at any point in the tax year — running a sole proprietorship, freelancing, or otherwise carrying on a business. There's also a spouse rule worth knowing: if your spouse or common-law partner was self-employed, your return gets the June 15 deadline too, even if you personally were a T4 employee all year with no business income at all.

What the rule doesn't touch is the payment date. Whether you're the self-employed partner or the employed one riding along on the spouse rule, any balance owing on either return was due April 30, 2026.

The trap: filing on time still costs you

It's easy to read "deadline: June 15" and assume you're fine until then. You're fine on the paperwork. You're not fine on the money. The CRA starts daily compound interest on any outstanding T1 balance the day after the balance-owing due date — May 1, 2026 for the 2025 tax year — and that clock runs whether you've filed or not. A self-employed filer who waits until June 15 to file and pay has, by definition, let interest compound for about six weeks on a bill they knew was coming.

None of this is a penalty for filing late — you filed on time, exactly as the rule allows. It's interest on money the CRA considers overdue regardless of your filing deadline. The two dates measure different things, and only one of them is optional.

The HST mirror: same trap, same fix

If you're a sole proprietor who files GST/HST annually, with a December 31 fiscal year-end and business income for the year, your HST return follows the identical pattern: the return isn't due until June 15, but the payment is due April 30. It's easy to miss because it mirrors the T1 split so closely — two different filings, same two dates, same trap if you treat June 15 as the only date that matters.

Where instalments fit in

The April 30 balance is about last year's taxes. Separately, the CRA may require quarterly instalments toward next year's taxes if your net tax owing was more than $3,000 (Quebec: $1,800) in the current year and in either of the two preceding years — a threshold self-employed income hits more often than T4 income, since nothing is withheld at source. Instalment payments are due March 15, June 15, September 15, and December 15 (farmers and fishers have a single December 31 date). Notice that June 15 shows up twice on a self-employed filer's calendar in one year — once as the filing deadline, once as an instalment due date. They're unrelated obligations that happen to land on the same day.

The practical move

Don't let the filing extension talk you out of paying on time. If your books are in good enough shape to estimate — even roughly — what you'll owe, pay that estimate by April 30 and finish the actual return whenever it's genuinely ready, up to June 15. An estimate paid on time and trued up later costs a fraction of what six weeks of daily compounding costs on the full balance.

The estimate is only as good as the bookkeeping behind it, which is the real reason this deadline catches self-employed filers more than employees: nobody's withholding tax from your invoices all year, so the number due April 30 has to come from somewhere. Books that are current through the year make that estimate a five-minute lookup instead of a March scramble. That's the whole case for keeping monthly books current rather than reconstructing a year in April — and it's the same reason our bookkeeping starts at $200/month with HST filings included, so the number you need by April 30 is already sitting there when you need it.