Estimate an early mortgage payoff by testing extra monthly payments, annual overpayments or a one-time lump sum. See how faster principal reduction can change payoff time and total interest.
Mortgage payment formulas, amortization schedules, extra principal and worked loan-payment scenarios.
Enter the current balance, interest rate and years remaining. Then add any extra monthly payment, annual principal payment or one-time lump sum. The calculator compares the strategy with the scheduled loan.
The result shows the scheduled payment, monthly payment with extra principal, estimated payoff date, months saved, baseline interest and estimated interest saved.
Interest is calculated monthly on the remaining balance. A one-time lump sum is applied immediately, the monthly extra is added to each payment and the annual extra is applied after each 12th payment while a balance remains.
| Strategy | What to enter | What to compare |
|---|---|---|
| Extra every month | Add a fixed extra principal amount | Months saved and interest saved |
| Annual overpayment | Add one extra principal payment each year | New estimated payoff date |
| Lump-sum payment | Apply a one-time principal reduction | Remaining balance and future interest |
See the full payment breakdown with the amortization schedule calculator, compare accelerated payments with the biweekly mortgage calculator, read how to calculate a mortgage payment, or estimate buying power with the home affordability calculator.
Imagine a remaining balance of $200,000, a fixed annual interest rate of 5.5%, and 20 years remaining. Start with the scheduled principal-and-interest payment. Then try an extra $200 each month directed to principal and compare the projected interest and months to payoff against the no-extra-payment case.
Assumptions: this is an amortization estimate, not a lender payoff statement. It generally excludes escrow, fees, changes in interest rates, and any prepayment penalties. Confirm that your mortgage servicer applies additional amounts to principal, rather than advancing the next payment due date.
On a standard amortizing fixed-rate loan, reducing principal earlier generally reduces future interest, assuming the lender applies the extra amount to principal.
No. It models principal and interest only.
See how formulas, sources and limitations are handled across ERICH Calculators.