Mortgage Payoff Calculator
Last updated: November 5, 2026
Estimate payoff time and total interest from a current balance and monthly payment.
Estimated payoff time
—
- Months to payoff: —
- Total interest: —
- Total paid: —
On this page
Quick summary: Estimate payoff time and total interest from a current balance and monthly payment.
Read the complete guide
Updated reference sections in this guide are in English.
What this calculator estimates
Estimate payoff time and total interest from a current balance and monthly payment.
How to use it
Enter Current mortgage balance ($); Interest rate (%); Monthly principal & interest payment ($); Extra monthly payment ($). Select Calculate to update the results.
How the calculation works
For each month, charge balance × annual rate/1200 in interest, then apply the regular principal-and-interest payment plus the extra payment. Cap the final payment at the amount still due. Count payments and add interest and payment amounts until the balance is repaid.
Worked example: starting scenario
| Current mortgage balance ($) | 250000 |
|---|---|
| Interest rate (%) | 6 |
| Monthly principal & interest payment ($) | 1800 |
| Extra monthly payment ($) | 200 |
| Estimated payoff time | 16 yrs 5 mo |
|---|---|
| Months to payoff | 197 |
| Total interest | $143,312.84 |
| Total paid | $393,312.84 |
Important limitations
The entered payment excludes escrow for taxes and insurance. The combined payment must exceed the first month's interest. The calculation has a 100-year simulation limit and excludes rate changes, lender rounding, fees, new borrowing and prepayment penalties.
The final month and supported horizon
Interest is added monthly before the entered payment and extra payment are applied. The final payment is limited to the balance plus that month’s interest, so it can be smaller than a regular payment. Completion in exactly 1,200 months is supported; a balance still outstanding after that month exceeds the 100-year simulation window.