Mortgage Acceleration Calculator
Compare a standard monthly mortgage schedule to an accelerated biweekly schedule to see how much time and interest you could save.
What Is Mortgage Acceleration?
Mortgage acceleration means paying off your loan faster than the standard schedule, most commonly by switching from monthly payments to biweekly payments. Paying half your monthly payment every two weeks results in 26 half-payments a year, the equivalent of 13 full monthly payments instead of 12, without a large change to your budget.
The Formula
The calculator first finds your standard monthly payment using the amortization formula M = P × [r(1+r)^n] / [(1+r)^n – 1]. It then simulates paying half that amount every two weeks, applying interest at the biweekly rate and reducing the balance until it reaches zero, tracking how many periods and how much interest that takes.
This tool is for general planning and educational purposes. Confirm with your lender that biweekly or extra payments are applied directly to principal without fees, since some servicers hold extra funds until a full payment accumulates.