Mortgage Payoff Calculator
See how much sooner you pay off your mortgage and how much interest you save with extra monthly, yearly, one-time or biweekly payments, or find the extra payment needed to be mortgage-free by a target year, with payoff dates and a full schedule.
How it works
Months left = log(payment ÷ (payment − balance × r)) ÷ log(1 + r), r = annual rate ÷ 12 · Each month: interest = balance × r, principal = payment + extra − interest · Repeat until the balance is 0 · Interest saved = interest on the current schedule − interest with extra payments · Goal mode: the smallest monthly extra that ends the loan within the target time
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. Start from whatever you know: today’s balance and monthly payment, today’s balance and the years left, or the original loan amount, term and time remaining (the calculator then works out your balance). It amortizes the loan month by month with your extra monthly amount, an optional extra payment once a year and a one-time lump sum, and compares the result with your current schedule. Switch to “Extra needed for a goal” to find the smallest monthly extra that clears the mortgage within the number of years you choose. You can also compare paying half the payment every two weeks, see the payoff dates, and read the yearly and monthly schedules. The payment should be principal and interest only; escrowed taxes and insurance do not reduce the balance.
Worked example
On a $250,000 balance at 6% with a $1,600 monthly payment, payoff takes 25 years 5 months and about $237,000 in interest. Adding $200 a month clears it in about 19 years 10 months and saves about $59,700 in interest. A $400,000, 30-year loan at 6% with 25 years left has a $2,398.20 payment and a $372,217.43 balance; paying $500 more each month ends it in 17 years 3 months instead of 25 years and saves about $122,306 of interest. To be mortgage-free in 15 years on the first loan, you would need about $510 extra a month ($509.65).
Sources: CFPB — Can I prepay my loan at any time without penalty? · Freddie Mac — Primary Mortgage Market Survey (weekly average rates)
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, keep an emergency fund, then split between extra payments and investing. With a 30-year rate near 7.4% in October 2026 (Freddie Mac), extra payments are a stronger option than when rates were 3%.
How much extra do I need to pay to finish by a certain year?
Choose “Extra needed for a goal” and enter how many years from now you want the mortgage gone. The calculator finds the smallest extra monthly payment that gets you there, counting any yearly or one-time extra payments you entered under More options.
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. Enter it as the yearly extra, or turn on the biweekly comparison under More options.
I don’t know my balance. Can I still use this?
Yes. Choose “Original loan” and enter the amount you borrowed, the original term and how long is left. The calculator works out today’s balance and payment from the standard amortization formula. Your servicer’s payoff statement is the exact figure, because it adds interest up to the payoff day and any fees.
Do extra payments lower my monthly payment?
No. Extra payments shorten the loan; the required payment stays the same. If you want a lower payment instead, ask your lender about a recast, where they re-amortize the smaller balance over the remaining term for a fee.
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This is an educational estimate, not financial or tax advice. Confirm figures with a professional.