Mortgage Payoff Calculator
See how extra monthly payments can shorten your mortgage and reduce interest.
Educational estimate only. This is not financial, investment, tax, legal or lending advice, a quote or a guarantee. Read the disclaimer.
Your inputs
How this calculator works
P is the current balance, r is the annual percentage ÷ 100 ÷ 12, and n is remaining years × 12. The scheduled payment is recalculated from these inputs; it may differ from your actual contractual payment. Two monthly simulations compare total interest and payoff months, reducing the last payment to the amount due. Extra money is assumed to reduce principal immediately. No escrow, fees, prepayment penalties, recasts or changing rates are included. Simulations stop at a residual of one cent or less or 1,200 months; an unfinished payoff is flagged.
Dollar results are in USD and generally rounded to the nearest whole dollar; salary equivalents and percentage outputs use two decimal places. Calculations retain JavaScript floating-point precision between steps rather than rounding every payment to cents. Displayed components may not sum exactly to displayed totals. Payoff times use whole monthly payment periods. Defaults are examples, not current rates or recommendations.
Full methodology · About the publisher and corrections
Content and calculation checks: October 12, 2026. Educational estimates; no independent professional certification is claimed.
Worked example: adding $200 per month
For the default $300,000 balance at 5.5% with 25 years remaining, the modeled scheduled payment is about $1,842 per month. Adding $200 raises the payment to about $2,042.
In this simplified model, the extra payment shortens payoff by about 55 months and reduces interest by about $53,092. Real loan servicing rules can differ, so confirm that extra amounts are applied to principal.
Practical guide
Before sending extra mortgage payments
- Confirm there is no prepayment penalty or special principal-payment process.
- Compare the benefit with other priorities such as high-interest debt, emergency savings or employer retirement matches.
- Run several extra-payment amounts instead of choosing one arbitrary number.
- Keep taxes and insurance separate; this calculator focuses on the loan balance and interest.
How to use the result
Change one assumption at a time to compare scenarios. For example, test a lower rate, larger contribution, different term or extra payment. This makes the calculator most useful as a decision-support tool rather than a single-number answer.
Important financial decisions can depend on taxes, fees, eligibility rules, lender policies, market returns and personal circumstances that this simplified calculator does not capture.
Frequently asked questions
Is this mortgage payoff calculator free?
Yes. SumStride calculators are free to use and do not require an account.
Are the results exact?
No. Results are estimates based on the values you enter and the assumptions described on this page. Real-world fees, taxes, rates, policies and timing can differ.
Does SumStride save my inputs?
No account is required. The calculator runs in your browser; SumStride does not need your entered values to perform the calculation.