Mortgage Payoff calculator
Save thousands of dollars in interest by increasing your monthly mortgage payment.
How the mortgage payoff calculator works
It re-amortizes your remaining balance both at your current payment and with an added principal amount, then compares the two. The extra dollars skip ahead and retire principal directly, so they avoid all the future interest that principal would have generated.
Worked example: with current loan balance of $240,000, interest rate of 6.50% and years remaining of 25, the mortgage payoff calculator shows interest you would save of $64,196.
- Current payment (P&I)
- $1,620.50
- New payment
- $1,820.50
- New payoff time
- 19.3 yrs
- Interest without extra
- $246,149
The formula
Interest saved = (total interest at the scheduled payment) − (total interest with the extra payment applied each month until the balance reaches zero).
Results are estimates for educational purposes and are not financial advice. Confirm exact figures with your lender, plan administrator or advisor.
Questions about the mortgage payoff calculator
Why do extra payments save so much interest?
Every extra dollar of principal removes the interest it would have accrued for the rest of the loan. Early in a mortgage that can be 20–30 years of avoided interest on each dollar.
Should I pay extra or invest the difference?
If your mortgage rate is higher than the after-tax return you could reliably earn elsewhere, paying down the loan is the guaranteed win. Otherwise investing may come out ahead — this tool shows the guaranteed savings side.
Does my lender apply extra payments to principal automatically?
Not always. Confirm the extra amount is applied to principal, not pre-paying the next scheduled payment, or the interest savings shown here will not materialise.
Is the Mortgage Payoff calculator free to use?
Yes. Every calculator on FinCalculators is completely free, with no sign-up, login or paywall. You can run as many scenarios as you like.