Mortgage Payoff Calculator: Extra Payments and Interest Savings

Mortgage Payoff Calculator

Compare your remaining mortgage with monthly, annual, or one-time extra principal payments.











How the mortgage payoff calculation works

This calculator starts with the payment needed to amortize the current principal over the remaining term. It then builds two month-by-month schedules: one with the scheduled payment only and one with your selected extra principal payments. The comparison shows the reduction in payoff time and interest.

Scheduled payment formula
M = P × r(1 + r)n ÷ [(1 + r)n − 1]

Here, P is the current balance, r is the monthly interest rate (APR ÷ 12), and n is the number of remaining monthly payments. At 0% APR, the scheduled payment is simply P ÷ n.

Extra-payment options

  • Monthly extra: added to every scheduled payment.
  • Annual extra: added after every 12th payment.
  • One-time extra: applied in the payment month you choose.

Extra amounts are treated as direct principal reductions. The final payment is automatically reduced so the model never pays more than the remaining principal plus that month’s interest.

Worked example

For a $250,000 remaining balance at 6.5% APR with 25 years left, the scheduled principal-and-interest payment is about $1,688 per month. Adding $200 each month shortens the payoff by several years and reduces total interest substantially. Enter your exact balance, rate, term, and extra-payment plan above to calculate the comparison.

Important limits

The estimate assumes a fixed interest rate and monthly compounding. It excludes escrow, property tax, homeowners insurance, mortgage insurance, lender fees, late charges, adjustable-rate changes, and prepayment penalties. Confirm that your lender applies extra funds to principal and does not charge a penalty before changing your payment plan.

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