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Mortgage Payoff Calculator

See what paying extra does to your mortgage. Enter your remaining balance, rate and current principal-and-interest payment, then add an extra monthly amount or a one-time lump sum. You get the new payoff time, how much sooner you finish and the interest you avoid.

Quick examples
$
%
$

Principal and interest only — leave out escrow for taxes and insurance.

$
$
Your numbers stay in your browser. Nothing is uploaded.
Months to pay off192
That is
16 years
Paid off sooner by
5 years 7 months
Interest saved
$62,600.87
Interest still to pay
$152,422.67
Months without extra payments
259
Balance by year with the extra payments
PeriodPrincipalInterestBalance

Saved setups

Save a set of inputs you reuse — your usual rate, your loan, your room sizes — and load it back in one tap.

    Your recent calculations

    Results you calculate here are kept on this device so you can come back to them.

      Formula

      Each month: interest = balance × rate ÷ 12; principal = payment + extra − interest
      Months to pay off = −ln(1 − balance × r ÷ payment) ÷ ln(1 + r), with r = rate ÷ 12, rounded up
      Interest saved = interest without extra payments − interest with them

      How to use it

      1. Enter the principal balance from your latest statement.
      2. Enter the interest rate and your monthly principal-and-interest payment, leaving out escrow.
      3. Enter an extra monthly amount, a lump sum, or both.

      Worked examples

      A $250,000 balance at 6.5% with an $1,800 payment, adding $300 a month

      Months to pay off
      192
      That is
      16 years
      Paid off sooner by
      5 years 7 months
      Interest saved
      $62,600.87
      Interest still to pay
      $152,422.67
      Months without extra payments
      259

      A $180,000 balance at 4% with an $1,100 payment and a $20,000 lump sum

      Months to pay off
      200
      That is
      16 years 8 months
      Paid off sooner by
      3 years 1 month
      Interest saved
      $21,372.36
      Interest still to pay
      $59,252.10
      Months without extra payments
      237

      Simple ways to pay extra

      Paying half your monthly payment every two weeks results in 26 half-payments, or 13 full payments a year instead of 12. Rounding the payment up, or adding one-twelfth of a payment each month, has the same effect. Make sure your servicer applies the extra to principal.

      Pay off early or invest?

      Each extra dollar earns a guaranteed return equal to your mortgage rate. At 6.5% that is hard to beat safely; at 3% a savings account may pay more. Clear higher-rate debt and build an emergency fund first, and check whether your loan has a prepayment penalty — most US mortgages do not. This is an estimate, not financial advice.

      Questions people ask

      How much faster will I pay off my mortgage with an extra $300 a month?

      On a $250,000 balance at 6.5% with an $1,800 payment, the loan ends in 16 years instead of 21 years 7 months — 5 years 7 months sooner — and you save $62,600.87 in interest.

      What does a $20,000 lump sum do?

      On $180,000 at 4% with an $1,100 payment it cuts the payoff from 237 months to 200 months and saves $21,372.36 in interest.

      Why does the calculator say my payment does not cover the interest?

      The payment entered is less than one month of interest on the balance (balance × rate ÷ 12), so the loan would never be repaid. Check that you entered the principal-and-interest payment and the right rate.

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