Paying a mortgage off early is one of the few financial moves with a guaranteed return: every extra dollar of principal stops accruing interest at your loan’s rate for the rest of the term. This calculator starts from the loan you already have, works out today’s balance from the original terms, and shows how extra monthly payments, a bi-weekly schedule, a lump sum or a fixed target date change the finish line.
How to use the mortgage payoff calculator
- Enter the original loan amount, interest rate and original term.
- Enter how many payments you have already made. Add your next payment date if you want calendar payoff dates.
- Choose a plan:
- Pay extra — an amount added every month, a one-time payment now, and/or a switch to bi-weekly half-payments.
- Pay off by a target date — the number of years from now when you want the loan gone.
- Compare the original schedule with your plan in the summary table, the balance chart and the month-by-month schedule.
Remaining balance formula
The balance left after k payments is the original loan grown at the loan rate, minus the payments grown the same way:
P is the original amount, r the monthly rate (annual rate ÷ 12) and M the regular principal-and-interest payment. For a target date of t months, the required payment is the annuity payment on B over t months, and the extra amount is that payment minus M.
Worked example
A $300,000 mortgage at 6.5% for 30 years has a payment of $1,896.20. After 60 payments the balance is about $280,832.93, with 25 years and $288,028 of interest still ahead.
Add $200 a month: paid off in 240 more payments (20 years) instead of 300, saving about $66,944 of interest.
Switch to bi-weekly: the extra $158.02 a month (one payment a year) finishes in 20 years, 10 months and saves about $55,861.
Target 15 years from now: you need $2,446.36 a month — $550.15 extra — and save about $128,517.
Choosing a payoff strategy
Extra monthly principal
The simplest approach and the easiest to automate. Because the money arrives every month, it starts saving interest immediately. Even small amounts matter most in the early years, when most of each payment is interest.
Bi-weekly payments
Paying half the monthly amount every two weeks produces 26 half-payments, or 13 full payments, a year. It suits people paid every other week. Some third-party programs charge setup fees for something you can do yourself by adding 1/12 of a payment each month.
Lump sums and recasting
A bonus, tax refund or inheritance applied to principal shortens the loan without raising your required payment. If you would rather lower the payment, ask whether your lender offers a recast, which re-amortizes the smaller balance over the remaining term for a modest fee.
When to think twice
Check for prepayment penalties, keep an emergency fund, and compare your mortgage rate with what you pay on other debts. If current rates are well below yours, the refinance calculator may show a bigger saving than prepaying. To model a brand-new loan instead, use the mortgage calculator or the amortization calculator.
Estimates only. The balance is reconstructed from the original terms and assumes on-time payments with no escrow changes or rate adjustments; your servicer's payoff statement is the official figure.
Frequently asked questions
How much faster will extra payments pay off my mortgage?
It depends on the balance, rate and how early the extra money arrives. On a $300,000, 6.5%, 30-year loan that is five years old, adding $200 a month cuts the remaining 25 years to 20 and saves about $66,900 of interest.
Do bi-weekly payments really help?
Yes, because 26 half-payments a year add up to 13 full payments instead of 12. That one extra payment a year goes entirely to principal. Make sure your servicer applies the money promptly and does not charge a fee for the program; you can get the same effect by adding one-twelfth of a payment to each monthly payment.
How do I figure out what extra payment I need to be mortgage-free by a certain date?
Choose the target-date plan and enter how many years from now you want the loan gone. The calculator finds the payment that amortizes your current balance over that period and subtracts your regular payment to show the extra amount needed each month.
Is my payoff amount the same as my remaining balance?
Not exactly. A payoff quote from your servicer adds interest accrued since the last payment and any fees, and it is only valid for a specific date. Use this calculator for planning and request an official payoff statement before sending a final payment.
Should I pay off my mortgage early or invest the money?
Prepaying earns a guaranteed return equal to your mortgage rate, while investing may earn more or less with risk. Many people first build an emergency fund, capture any employer retirement match and clear higher-rate debt before making extra mortgage payments.