Mortgage Payoff Calculator
One path adds a little every month. The other drops a lump sum once. They are not added together, because that would brag about savings you did not actually stack.
Written for Equidwell and last checked in October 2026. We build the calculators on this site. We are not a lender, and this page is not advice for your loan.
How this calculator works
- The current path amortizes the balance at the rate and remaining term you enter.
- The extra-monthly path adds the same extra amount to every payment.
- The one-time path applies a single extra amount on the first payment.
- Interest saved is the current path's interest minus the alternative path's interest.
A lower payment and an earlier payoff are different goals
Extra principal does not shrink the bill you are required to pay, unless the servicer recasts the loan. It shrinks what you owe, which can cut interest and pull the payoff date forward.
Pick one comparison. Stacking the extra monthly amount and the lump sum would count the same dollar twice, so this page refuses to.
Sources
Common questions
Is there a prepayment penalty?
This calculator does not know your note. Some loans restrict prepayment. Check the note or ask the servicer before assuming extra principal is free to send.
Which path saves more?
It depends on the amounts you enter. The page shows interest saved and months saved for each path against the current schedule.
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- Mortgage Refinance Calculator
Compare your current mortgage payment with a new rate and term. Break-even appears only when the new payment is lower.
Longer guides on these topics are linked from the guides library.