How much capital gains tax will I pay in Canada when I sell an asset?

This answer covers Canadian federal tax law, which applies in every province.

The tax depends on your gain and your other income, because there is no separate flat rate. Half of your capital gain is the taxable capital gain, and if it exceeds your allowable capital losses, the difference is added to your other income and taxed at your marginal rates.

Start by working out the gain: proceeds of disposition minus the adjusted cost base and the outlays and expenses of selling. In the CRA's example, shares sold for $6,500 with a $60 commission and a $4,000 ACB give a gain of $2,440, and half of that, $1,220, is the taxable capital gain reported on line 12700. That $1,220 is then taxed at your marginal rates along with your other income. A higher income pushes the taxable part into a higher bracket, so the same gain can cost different people different amounts.

Your actual bill depends on your total income, any capital losses, and whether an exemption such as the principal residence exemption or the lifetime capital gains exemption applies. Net capital losses can be applied only against taxable capital gains, but an allowable business investment loss can be deducted against other income. An accountant can run the numbers for your situation.