See how much interest you save and how many years you cut by adding extra payments to your mortgage.
What if you paid a different extra amount?
| Extra per month | Payoff time | Time cut | Total interest | Interest saved |
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🔒 This tool runs entirely in your browser. Nothing you enter or upload is sent to our servers.
How to use the Mortgage Payoff Calculator
- Enter your current loan balance, interest rate and the years remaining.
- Add an extra monthly payment, a yearly lump sum (e.g. a bonus) and/or a one-time payment now.
- Read the interest saved, the time cut from your loan and your new payoff date. The what-if table shows other extra amounts.
About this tool
Every extra dollar you pay goes straight to principal, so it stops accruing interest for the rest of the loan. Early in a mortgage most of each payment is interest, which is why small extra payments have an outsized effect: on a 30-year loan, an extra 10% each month typically cuts around 6 years and a fifth of the total interest.
The calculator rebuilds your amortization schedule month by month: interest is charged on the remaining balance at the annual rate divided by 12, your regular payment plus any extra is applied, and the loop runs until the balance reaches zero. Your regular payment is computed as P = B × r / (1 − (1 + r)−n) where B is the balance, r the monthly rate and n the remaining months.
Frequently asked questions
Should I pay off my mortgage early or invest?
Paying extra earns a guaranteed return equal to your mortgage rate. If you can reliably earn more after tax elsewhere (and have an emergency fund), investing may win; if your rate is high or you value being debt-free, prepaying is hard to beat.
Does a one-time lump sum or a monthly extra save more?
For the same total amount, money paid sooner saves more interest, so a lump sum today beats the same amount spread over the year. But a steady monthly extra is easier to sustain, and consistency matters most.
Are there prepayment penalties?
Most residential mortgages allow extra principal payments without penalty, but some loans (especially outside the US) cap annual overpayments, commonly at 10% of the balance. Check your loan terms.
Does this include taxes and insurance?
No. Enter only the principal-and-interest part of your payment. Escrow amounts for tax and insurance don’t affect the payoff math.