If you don’t have any amounts carried forward from previous years, then the credit would be calculated by multiplying your tuition by 15% (the lowest tax rate). However, the tuition credit is non-refundable. This means that you can only get the credit if you have taxes owing. If you don’t have taxes owing, or you have tuition credit remaining after reducing your taxes your zero, then the amount will carry forward to future years. It will continue to carry forward until it’s all used up.