Mortgage Payoff Calculator
See how much sooner you pay off your mortgage and how much interest you save by adding an extra amount each month.
How it works
Months = log(payment ÷ (payment − balance × r)) ÷ log(1 + r), r = annual rate ÷ 12 — compared with and without the extra payment
Every month interest is charged on the remaining balance and your payment covers that first; the rest reduces principal. An extra payment goes entirely to principal, which shrinks every future interest charge — so it both shortens the term and cuts total interest. The effect is largest early in the loan, when the balance and the interest it generates are at their highest.
Worked example
On a $250,000 balance at 6% with a $1,600 monthly payment, payoff takes about 25 years 5 months and roughly $237,000 in interest. Adding $200 a month clears it in about 19 years 10 months and saves close to $60,000 in interest.
Frequently asked questions
Is it better to pay extra or invest it?
Paying extra on the mortgage is a guaranteed return equal to your interest rate. Investing might earn more but carries risk. Many people do both — capture any employer retirement match first, then split between extra payments and investing.
Will my lender apply the extra to principal?
Not automatically — some apply extra to the next payment instead. Tell your servicer, in writing if needed, to apply additional amounts directly to principal, and check that your loan has no prepayment penalty.
Does one extra payment a year help?
Yes. Making 13 payments a year instead of 12 (or paying half your payment every two weeks) typically cuts several years off a 30-year mortgage and saves tens of thousands in interest.
Related calculators
This is an educational estimate, not financial or tax advice. Confirm figures with a professional.