If you are required to pay provincial income surtax, then your actual saving will be more than the charitable tax credit calculated as the credit will reduce both your base income taxes and provincial surtax.

Doing so will reduce the tax payable by that spouse and thereby minimize (or avoid) liability for the provincial high-income surtax.

Doing so will reduce the tax payable by that spouse and thereby minimize (or avoid) liability for the provincial high-income surtax.

Once you've made at least $200 of donations in any year, however, the donation credit jumps to 29% federally, plus between 11% and 21% provincially (ignoring any additional provincial surtax savings).