Core deadlines reviewed September 6, 2026
Monthly and quarterly GST/HST returns and payments are normally due one month after period-end. T2 filing is six months after taxation year-end, while the corporate balance is generally due after two months, or three months for CCPCs meeting the conditions. Federal business-corporation annual returns follow the anniversary; covered Ontario corporate annual returns follow taxation year-end. Those clocks should be recorded separately even when two dates happen to coincide.
2026 deadline examples
The table assumes the stated reporting period and entity eligibility. Confirm each item against the account or registry before assigning it to your business. For a federal corporation, the annual-return reminder and ISC filing belong together; Ontario annual-return requirements depend on the corporation covered by the provincial instructions.
| Obligation | Usual timing | Illustrative due date |
|---|---|---|
| Monthly GST/HST: August 31, 2026 period-end | One month after period-end | September 30, 2026 |
| Quarterly GST/HST: September 30, 2026 period-end | One month; CRA weekend rule applies | November 2, 2026 |
| T2: December 31, 2025 year-end | Six months after year-end | June 30, 2026 |
| Corporate tax balance: December 31, 2025 year-end | Two months; three if qualifying CCPC | March 2, 2026; qualifying three-month date March 31 |
| Federal business-corporation annual return and ISC: June 15 anniversary | Within 60 days after anniversary | August 14, 2026 |
| Covered Ontario corporate annual return: December 31, 2025 year-end | Within six months after year-end | June 30, 2026 |
| ISC register change recorded June 1, 2026 | Generally within 15 days of register change | June 16, 2026 |
An illustrative Ottawa planning week
An Ottawa consulting owner can set an October 20 internal close for a September 30 quarterly GST/HST period, leaving time to resolve supplier documents before the filing and payment date. CRA’s next-business-day rule moves the October 31, 2026 Saturday deadline to November 2. Keep the earlier preparation date even when the statutory date moves. The person approving the return and the person scheduling payment should both see that calendar entry.
Add the obligations that depend on the business
Payroll remittance frequency follows the CRA remitter type; do not assume every employer remits monthly. Annual GST/HST filers have different filing and payment rules, and instalments can be a separate requirement. Add applicable accommodation-tax reporting, EHT, workers compensation, municipal licences and professional renewals from the business’s actual notices. Attach the current source and renewal document rather than inventing one common anniversary for every permit.
Store evidence and handle changes promptly
CRA applies next-business-day rules for recognized weekends and holidays, but confirm the relevant authority’s rules for other filings. Allow time for payment processing. Save acceptance and payment confirmations beside each entry and update the calendar when filing frequency, ownership, address or business activity changes. ISC register changes generally need filing within 15 days, so an annual reminder alone is insufficient. The calendar works when someone owns each action and unresolved evidence stays visible.
Put this into practice
Sources and current guidance
A practical next step
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