Corporate Tax Filing Deadlines & Penalties in Ontario

Every corporation in Ontario has to file a T2 return every year — even if it made no money, or made none at all. Missing the deadline is more expensive than most owners assume, and the penalties compound the longer a return stays unfiled. Here's what actually happens.

When your T2 return is due

Your T2 corporate tax return is due six months after the end of your corporation's fiscal year. If your fiscal year ends December 31, your return is due June 30 of the following year. If your fiscal year ends March 31, your return is due September 30. There's no extension available just for asking — the six-month clock is fixed to your specific year-end.

When your balance owing is due — it's earlier than the filing deadline

This is the detail that catches business owners off guard: the deadline to file your return and the deadline to pay any tax owing are different. Balance-owing payments are generally due two months after your fiscal year-end — three months for eligible Canadian-controlled private corporations that meet certain conditions. That means you can owe interest on unpaid tax well before your actual filing deadline arrives, if you wait until the six-month mark to deal with it.

What a late filing actually costs

If you file late and owe tax, the corporation is charged a late-filing penalty calculated as a percentage of the unpaid tax, plus an additional amount for each full month the return remains outstanding, up to a maximum number of months. If the CRA has previously charged a late-filing penalty and you're late again within a few years, the penalty rate increases substantially. On top of the penalty, interest accrues daily on both the unpaid tax and the penalty itself, compounding the longer it goes unresolved.

The penalty and interest are calculated on the balance owing — so a corporation with a large tax bill and a late return faces a meaningfully larger total cost than one with a small balance owing.

Do you still have to file if the corporation had no activity?

Yes. A dormant or inactive corporation still has to file a T2 return every year it exists, even with zero income and zero activity. There's no filing exemption for inactivity — only for corporations that have been formally dissolved. Many business owners let this slip after a corporation stops operating, and the CRA can still charge late-filing penalties on a nil return.