Do I owe tax when I sell my house in Alberta?

This answer covers the law of Alberta.

You usually do not owe tax if the home was your principal residence for every year you owned it and you designate it, because the gain is generally exempt. You still have to report the sale on Schedule 3 of your return, since the CRA allows the exemption only if the sale and designation are reported.

The home must be one you own, and it must be ordinarily inhabited in the year by you, your spouse or common-law partner, a former spouse or partner, or your child. Only one home can be designated as your family's principal residence for each year. In the year you sell one home and buy another, the "plus 1" rule can let both be treated as eligible.

Tax can apply when the home was not your principal residence for every year, because you report the part of the gain tied to the years it was not designated. A home owned for less than 365 consecutive days and sold on or after January 1, 2023 is generally treated as business income instead, with exceptions for certain life events, including the death of the taxpayer or a related person, and for destruction or expropriation of the property. An accountant or lawyer can confirm how this applies to you.