Mortgage Payoff Calculator (2026)
See how much faster you could be mortgage free, and how much interest you could save, by adding a little extra to each monthly payment. Everything runs in your browser; nothing is stored or sent anywhere.
Estimate updates as you type. Set the extra amount to 0 to see your baseline payoff.
How the payoff calculation works
The calculator first finds your scheduled monthly payment from the balance, the interest rate, and the years remaining, using the standard amortization formula. It then simulates the loan month by month two ways: once with only the scheduled payment, and once with your extra amount added on top. Because the extra money reduces principal immediately, less interest accrues each following month, so the balance reaches zero sooner. The difference between the two payoff dates is your time saved, and the difference in total interest paid is your interest saved.
Why even a small extra payment matters
On a long mortgage, most of each early payment goes toward interest, not principal. Adding a modest amount that goes straight to principal compounds in your favor: it shrinks the balance, which lowers next month's interest, which leaves more of the following payment to attack principal. The effect is largest when your rate is high and many years remain. Always confirm the extra is applied to principal and that no prepayment penalty applies.
Common questions
Does this include property tax and insurance?
No. It models only loan principal and interest. Your real monthly bill may also include escrow for property tax, homeowners insurance, and sometimes mortgage insurance, which extra principal payments do not change.
What if my rate changes?
This tool assumes a fixed rate for the whole term. If you have an adjustable-rate mortgage, the payment and payoff date can move when the rate resets, so treat the result as a snapshot at today's rate.
Is my data saved?
No. The calculation runs entirely in your browser. Nothing you type is stored, transmitted, or shared.
Method: scheduled payment from the standard amortization formula; payoff and interest computed by month-by-month simulation with and without the extra principal payment. General references include published explainers from NerdWallet, Bankrate, and Calculator.net. Always verify your actual figures and prepayment terms with your lender.