What happens if I file my taxes late in Canada?

How the penalty actually compounds

The first-time late-filing penalty is 5% of the unpaid balance plus 1% per complete month the return remains outstanding, capped at 12 months. A return six months late with $20,000 owing attracts $1,000 plus $1,200, so $2,200 before interest.

The repeat penalty is where it becomes punitive. If the CRA issued a formal demand to file, and you were charged a late-filing penalty in any of the three preceding years, the rate doubles to 10% plus 2% per month for up to 20 months. The same $20,000 balance becomes $2,000 plus $8,000.

Note the base: penalties apply to the balance owing. If you file late but owe nothing, there is no late-filing penalty — though you may still delay benefits and credits.

Interest runs separately and daily

Interest is charged on top of penalties, compounded daily, from the payment due date. The CRA sets the prescribed rate quarterly and it has run materially above commercial lending rates in recent years.

Critically, interest is charged on the penalty as well as the tax. And unlike a business loan, interest on overdue tax is not deductible. This is why filing on time and paying late is almost always cheaper than filing late — the filing penalty is the larger and faster-growing component.

The deadlines that actually apply to you

• Personal (T1) — 30 April. Self-employed individuals and their spouses have until 15 June to file, but any balance owing is still due 30 April.
• Corporate (T2) — six months after fiscal year-end. Balance owing is due two months after year-end, or three months for a CCPC claiming the small business deduction.
• GST/HST — depends on filing frequency; annual filers with a 31 December year-end generally file by 30 June.
• Payroll remittances — by the 15th of the following month for regular remitters, with accelerated schedules for larger payrolls.
• T4/T5 slips — last day of February.

The corporate structure catches people out most often: the return is due at six months but the money is due at two or three. Filing on time does not stop interest running on an unpaid balance.

Payroll penalties are far harsher

Source deductions are held in trust for the Crown, and the CRA treats failure to remit them very differently from other late payments. The penalty is 3% to 10% depending on how late, rising to 20% for a second or subsequent failure in the same calendar year where it was made knowingly or through gross negligence.

Directors can also be held personally liable for unremitted source deductions and GST/HST. Incorporation does not shield you from this, which makes payroll remittance the single most important date in a business owner's calendar.

The Voluntary Disclosures Program

If you are behind, the VDP may cancel penalties and part of the interest. To qualify the disclosure must be genuinely voluntary — made before the CRA contacts you about the issue — as well as complete, involve a potential penalty, and include information at least one year overdue.

The programme is materially less generous than it once was, and applications are assessed on their facts. The critical point is timing: once the CRA opens an enquiry, the door closes. If you know you are behind, acting now preserves an option that disappears the moment a letter arrives.

What to do if you cannot pay

File anyway. The filing penalty is the largest and fastest-growing charge, and it applies whether or not you can pay. Filing on time with a nil payment stops that penalty entirely and leaves only interest running.

The CRA will generally agree a payment arrangement if you contact them and can demonstrate the plan is realistic. Taxpayer relief provisions may also cancel penalties and interest in cases of serious illness, natural disaster, or CRA error or delay — but relief is discretionary and requires a documented application.