If you file your corporate income tax return late, the penalty is 5% of the unpaid tax that is due on the filing deadline, plus 1% of the this unpaid tax for each complete month that the return is late, up to a maximum of 12 months.
If the Canada Revenue Agency (CRA) sent you a demand to file the return and they assessed a failure to file penalty for the corporation in any of the three previous years, the penalty is 10% of the unpaid tax when the return was due, plus 2% of this unpaid tax for each complete month that the return is late, up to a maximum of 20 months.