How to use the Mortgage Payoff Calculator
The mortgage payoff calculator shows how much sooner you finish your loan, and how much interest you save, by paying extra each month.
Open the Mortgage Payoff Calculator →
What you need to enter
- Remaining balance ($)
- Interest rate (%)
- Current monthly payment ($)
- Extra monthly payment ($)
The formula
Months to pay off = −ln(1 − B × r ÷ payment) ÷ ln(1 + r), where B is the balance and r the monthly rate. The tool compares your current and increased payments.
Worked example
Using the default values in the calculator:
- Remaining balance ($): 250000
- Interest rate (%): 6
- Current monthly payment ($): 1500
- Extra monthly payment ($): 200
| Time saved | 7 yr 9 mo |
| Payoff without extra | 30 yr 0 mo |
| Payoff with extra | 22 yr 3 mo |
| Interest saved | $85,835.49 |
Tips for better results
- Even a small extra payment early on has a big effect on interest.
- Make sure extra payments go to principal, not to the next due payment.
Common mistakes to avoid
- Not checking for prepayment penalties.
- Using savings you may need for emergencies.
Please note: Calculators and guides give general estimates, not financial, tax or investment advice. Real offers depend on your lender, location and personal situation. See our Disclaimer.