Question: When is the Canadian taxes due date?
The Canadian taxes due date depends on how your business is structured.
If your business is a sole proprietorship or partnership, you will declare your business income on your T1 Personal Income Tax Return, and will have to pay any income tax balance owing by April 30th, assuming that your business's fiscal year ended on December 31, which is the case with most businesses.
Oddly, however, "if you have self-employment income, or are the spouse or common-law partner of someone who does, unless the expenditures of the business are mainly the cost or capital cost of tax shelter investments" (Canada Revenue Agency), you have until June 15th to file your income tax return.
Even if you're not filing your income tax until June 15th, though, you still need to pay any income tax due by April 30th, to avoid income tax penalties.
If your business is a corporation and the corporation has a balance owing on its corporate income tax, for most corporations, that tax balance must be paid within two months after the end of the tax year (the fiscal year end), except for Canadian-controlled-private corporations, that may have three months to pay their income tax balance if certain conditions are met.
(Note that some businesses may change their fiscal year end if they wish.)
For information on filling out your first business income tax return see: