➕ Mortgage with Extra Payments Calculator
See how much time and interest you can save by adding an extra amount to your monthly mortgage payment.
How Extra Payments Help
Adding even a modest extra amount to your monthly mortgage payment goes entirely toward reducing your principal balance, since your required interest is already covered by the standard payment. A smaller balance means less interest accrues going forward, which compounds into significant savings and a shorter loan term.
The Formula
The calculator first computes your standard monthly payment with M = P × [r(1+r)^n] / [(1+r)^n – 1], then simulates paying that amount plus your extra payment each month, recalculating interest on the shrinking balance until it reaches zero, and compares the results to the original schedule.
This tool is for general planning and educational purposes. Confirm with your loan servicer that extra payments are applied directly to principal rather than held or applied to future scheduled payments.