Your monthly payment = P x [ I (1 + I ) T ] / [ (1 + I ) T − 1] This formula only tells you what you’ll owe to pay off principal (your mortgage balance) and interest. Make sure you add in ...

Useful, right? You can build this into a spreadsheet template that allows you to experiment with different payoff periods (and how much money you can save by paying off a loan early). Note that this ...