Mortgage Payoff Calculator
See how adding to your monthly payment shortens your mortgage and slashes the interest you pay.
How the mortgage payoff calculator works
Adding even a modest amount to your monthly payment can dramatically shorten a mortgage, because every extra dollar goes straight to principal and stops accruing interest for the rest of the loan. This calculator takes your remaining balance, rate, and current payment, then re-amortizes the schedule with your additional contribution applied each month.
The result shows how many months or years you shave off the term and how much total interest you avoid. The effect is largest early in the loan, when the balance and the interest portion of each payment are both at their peak.
Worked example: with current loan balance of $240,000, interest rate of 6.75% and years remaining of 25, the mortgage payoff calculator shows interest you would save of $67,959.
- Current payment (P&I)
- $1,658.19
- New payment
- $1,858.19
- New payoff time
- 19.3 yrs
- Interest without extra
- $257,456
| Extra monthly payment | Interest you would save |
|---|---|
| $150 | $54,921 |
| $300 | $89,255 |
| $500 | $119,537 |
| $750 | $144,413 |
The formula
The remaining balance is re-amortized with each payment split into interest, equal to the balance times the monthly rate, and principal, which absorbs everything left over including your extra amount. Iterating month by month until the balance reaches zero yields the new payoff date and cumulative interest.
- The extra payment is applied to principal every month without interruption for the full remaining term.
- Your lender credits additional payments to principal immediately and charges no prepayment penalty.
- The interest rate is fixed; a variable rate would change the savings as it adjusts over time.
- Escrowed taxes and insurance are excluded, since only principal and interest are affected by prepayment.
- Results ignore inflation and any return you might earn by investing the extra money instead.
Results are estimates for educational purposes and are not financial advice. Confirm exact figures with your lender or a licensed advisor.
Questions about the mortgage payoff calculator
Is it better to pay extra each month or make one lump sum a year?
Monthly extras win slightly, because the money reduces your balance sooner and starts saving interest earlier in the year. A single annual lump sum still helps meaningfully and suits people paid through bonuses or tax refunds.
The gap between the two methods is small, so choose whichever cadence you will actually sustain.
Should I pay down my mortgage or invest the extra money instead?
Compare your mortgage rate to your expected after-tax investment return. Prepaying delivers a guaranteed return equal to your rate, which is attractive when rates are high or markets feel uncertain. Investing may win over long horizons but carries risk.
Many borrowers split the difference, paying some extra principal while still funding retirement accounts.
Will extra payments lower my required monthly bill?
Usually not. Standard prepayment shortens the term but leaves your scheduled payment unchanged, so you finish the loan sooner rather than paying less each month.
To reduce the required amount you would need a formal recast, where the lender re-amortizes the lowered balance over the original term, often for a small fee.
Is the Mortgage Payoff Calculator free to use?
Yes. Every calculator on MortgageLoansCalculator is completely free, with no sign-up, login or paywall. Run as many scenarios as you like.
How can I pay off my mortgage faster?
Add extra to principal each month, switch to biweekly payments, or make a lump-sum payment — each cuts the term and total interest, since interest is charged on the remaining balance. Test any amount above to see the new payoff date.
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