It seems that every year there are at least two tax deadlines: The RRSP Deadline  and the tax filing deadline.
If you are self-employed, you should be aware that your taxes are due before you file your income tax return.
Knowing when to pay your taxes will help you avoid expensive and costly interest and penalties.
See all of the deadlines on the Canadian Tax Deadline Calendar .
Filing Due Dates
The date you must file your personal income taxes is the filing date. For most people, midnight April 30th is the due date.
If you are self-employed, then you don’t have to file your tax return until June 15th (however, you still have to pay any tax owing by April 30th! – see below).
If you are preparing a return for a deceased person, the deadline depends on when the person passed away. If the death occurred between January 1st and October 31st (inclusive), the return is due April 30th of the following year or June 15th if they were self-employed. Otherwise, the return is due 6 months following the date of death.
For trusts, the deadline to file the T3 trust return is 90 days following the end of the tax year.
Tax Payment Deadlines
Individuals who are self-employed must pay their income taxes no later than April 30th. This is regardless of when you had to file the income tax return!
Certain individuals must pay their taxes in instalments. If you have net tax owing that is $3,000 or more in the current and either of the prior two years, or if you are a farmer or fisher, you may have to pay tax by instalments.
To find out more about paying by instalments, see the CRA site on this topic .
Penalties For Being Late
Failure to File For Individuals: Failure to file your income tax return may be subject to a penalty of 5% of the unpaid tax owing plus 1% per month the return is not filed (12 months maximum).
Interest On Past Due Balances: The CRA may also charge interest on the unpaid balance. This is set at the prescribed rate  for overdue balances.
If you have a corporation, tax returns must be filed within six months of year end. Taxes must be paid within three months of year end for Canadian controlled private corporations (CCPC)  and within two months for all other corporations.