Enter your current mortgage balance, rate, and payment — plus an optional extra monthly payment — to see how much sooner you'd pay it off and how much interest you'd save.
How to Use the Mortgage Payoff Calculator
Current balance, rate, and payment describe the loan as it stands; the extra-payment field is what actually gets compared against — leave it blank and there's nothing to measure the baseline against.
An extra $200 a month sounds small next to a six-figure mortgage balance, but because it goes straight to principal rather than being split with interest, its effect on the total payoff timeline is usually bigger than the raw dollar amount suggests.
This calculator simulates the loan month by month, twice — once at the current payment, once with the extra amount added — tracking the balance down to zero each time. There's no closed-form shortcut for "how much does an extra payment save," since the savings depend on exactly when in the amortization schedule the extra money starts landing; simulating it directly is the only reliable way to get an accurate answer.
The earlier extra payments start, the more interest they avoid, because they're cutting balance at the point in the loan where interest charges are highest. The same extra amount applied in year 25 of a 30-year mortgage does far less than applying it in year one.