Corporate Tax Filing Deadline: Penalties, Interest, and What to Do If You're Late

Wondering when your business taxes are due, including your corporate tax filing deadline? Many business owners assume it's a single date. It isn't, and that mix-up costs Canadian SMEs real money every year.

At T2inc.ca, our tax accountants follow up regularly with every client to help them stay on top of their small business tax deadlines. Even so, we still see businesses file too late, or simply forget to file at all. That's especially true for new businesses with little activity so far.

Here's how to meet your corporation tax filing deadline, and what to do if you're already late.

What Is the T2 Filing Deadline for Corporate Tax Returns?

Every corporation incorporated in Canada must file a T2 corporate tax return within six months of its fiscal year-end. This obligation comes from paragraph 150(1)(a) of the Income Tax Act, which applies to every corporation resident in Canada, and a corporation incorporated here is automatically considered resident under the Act.

This deadline doesn't distinguish between an actively growing small business, a holding company sitting on investments, an inactive corporation with no activity for the year, or one that's in the middle of dissolving. The clock is the same for all of them. What triggers it is the corporation's legal existence, not what it did or didn't do during the year.

Unlike a personal tax return, which falls on the same date every year (April 30), your T2 due date always follows your own fiscal year-end:

• Year-end December 31 → return due June 30
• Year-end March 31 → return due September 30
• Year-end June 30 → return due December 31
• Year-end September 30 → return due March 31

If that date falls on a Saturday, Sunday, or public holiday, you have until the next business day, with no penalty. The Canada Revenue Agency (CRA) applies this extension automatically.

Two situations deserve closer attention.

Just Incorporated Your Business?

Your first fiscal year almost never lasts a full 12 months. If you incorporate on May 4 and set your fiscal year-end at August 15, your first tax year only covers the days between those two dates. Every following fiscal year goes back to a normal 12-month period, calculated from August 15.

Dissolving Your Corporation?

Dissolving your corporation doesn't release you from your tax obligations. Your fiscal year ends on the date of dissolution, not before. From that date, you still have six months to file your final return.

Is the T2 Payment Deadline the Same as the Corporate Tax Filing Deadline?

No. The corporate tax payment deadline isn't the same as your business tax filing deadline. The law sets these two dates separately, and that's a big part of why new businesses fall behind.

Generally, you must pay any balance owing within two months of your fiscal year-end. If your corporation is a CCPC (Canadian-controlled private corporation) that qualifies for the small business deduction, that window stretches to three months.

Take a corporation with a fiscal year ending December 31. Its T2 return is due June 30. But its balance owing is due February 28, or March 31 if it's an eligible CCPC. You could file your T2 in June without missing anything on the filing side, and still owe interest that's been accumulating since February or March.

Corporate Tax Instalments: Avoiding a Bad Surprise

If your federal tax bill exceeds $3,000 for the current year, or exceeded it in either of the two previous years, the CRA requires your small business to make instalment payments throughout the year instead of one lump sum at the end. This spreads out the cost, and it keeps you from facing a balance too large to absorb all at once.

Paying Online, and Filing Electronically

Online payment remains the fastest and simplest method. And since 2024, all corporations must file their T2 return electronically, regardless of their gross revenue.

What Is the Penalty for Filing Corporate Taxes Late?

Missing the corporate tax filing deadline for the first time triggers what's commonly called the T2 late filing penalty: 5% of the balance owing, plus 1% for every full month of delay, up to a maximum of 12 months. Paying late costs interest on top of that. Miss both deadlines, and the two costs stack.

Corporate Tax Late Filing Penalty: The Exact Calculation

Take a concrete example. Your corporation owes $20,000 in tax and files its return three months after the deadline. The penalty is 5% ($1,000), plus 3% for the three months late ($600), for a total of $1,600. And that's before counting the interest still accruing on the balance.

If your business has already been hit with this penalty within the past three tax years, a repeat offense nearly doubles the bill: 10%, plus 2% per month, up to 20 months.

Interest Never Stops

Unlike the penalty, which is a fixed amount, interest compounds daily on any unpaid balance. It keeps accruing for as long as the debt goes unpaid.

The rate changes every quarter, which makes any reference figure go stale fast. For July through September 2026, the CRA set it at 7%, but never assume that number holds true the following quarter.

Are Corporate Tax Deadlines Different by Province?

For filing, no. Whether you're in Ontario, in Quebec where you also have to file a CO-17 return, in Alberta with your AT1, or anywhere else in the country, the six-month rule stays exactly the same. It's payment where things start to differ.

Paying Is Where It Diverges

In Quebec, the payment deadline stays fixed at two months, no exceptions. Even an eligible CCPC that gets a third month federally doesn't get one provincially.

In Alberta, payment follows its own rules, administered directly by the TRA (Tax and Revenue Administration).

The same divergence applies to interest on an unpaid balance. The federal government and Quebec each calculate their own rate independently, and the two figures don't always match.

CO-17 and AT1: A Separate Return and Penalty From the Federal One

Quebec and Alberta each require their own return, on top of the federal T2. Each one triggers its own penalty, assessed separately.

Both provinces use the same formula as the federal government: 5% of the balance owing, plus 1% per month of delay.

Both provinces also require electronic filing, regardless of gross revenue. In Quebec, that requirement has applied to CO-17 returns since taxation years beginning in 2024. In Alberta, it's applied since 2025. In both cases, failing to comply triggers a separate $1,000 penalty.

In the other 11 provinces and territories, including Ontario and British Columbia, there's just one return and one penalty. The CRA calculates it on the combined balance, with a single notice of assessment and a single point of contact.

Can CRA Penalties and Interest Be Cancelled?

Yes, under certain conditions. A penalty or interest charge that's already been applied isn't necessarily final.

If your delay was caused by serious illness, a disaster, a death in your immediate family, or an error attributable to the tax authority itself, you can request a cancellation or reduction. Three authorities, three forms, but the same principle:

• Federally: Form RC4288
• In Quebec: Form MR-94.1, with nearly the same accepted grounds
• In Alberta: Form AT4764, administered by the TRA

Nothing is automatic. You need to document your situation and provide supporting evidence, and the clearer your file, the better your chances of being heard.

Putting together this kind of file on your own is rarely simple, especially in the middle of a crisis. Our clients get support from our tax accountants for this exact process. If you're not a client yet, our partner accountants can also point you in the right direction.

Not to Be Confused With: The Voluntary Disclosures Program

If your delay spans several years rather than a single missed fiscal year, a different mechanism applies: the Voluntary Disclosures Program (VDP). The CRA, Revenu Québec, and Alberta each run their own.

Already Filing Your Corporate Taxes Late? Here's What to Do

An oversight, a tougher year than expected, an accountant you couldn't reach in time. Whatever the reason, nothing is irreversible. Here's the order of priorities.

File Now, Even If You Can't Pay Yet

This is rule number one. The late-filing penalty is often steeper than the interest on an unpaid balance. File your return as soon as possible, even if you have to settle the balance a little later, with help from our tax accountants if you'd rather not handle it alone.

Negotiate a Payment Arrangement

You have the right to propose a realistic payment schedule to the CRA or Revenu Québec. Interest keeps accruing, but a well-documented request is usually accepted without complication.

Outsource to Professionals

Meeting deadlines, filing the right forms, avoiding costly mistakes: that's exactly what tax accountants are for. And their fees often cost less than a single penalty you would have otherwise paid.

Set Up a Simple Routine

Note your deadlines as soon as your fiscal year ends, set automatic reminders, and keep your accounting records up to date year-round. The goal is to make this a habit, not a scramble every year.

T2inc.ca Handles Your Late Corporate Tax Return

A late corporate tax return can happen to anyone. What matters is what comes next: the longer you wait, the more it costs, and acting now is always simpler than acting six months from now.

Even if you don't have all your documents yet, even if several years have piled up, get a free quote for your late return. We'll take care of the rest, whether it's a single missed T2 return or a late filing penalty on a corporate tax return that's already accumulated interest.

FAQ — T2 Filing Deadline