See how paying a little extra each month can shorten your mortgage and cut total interest. Enter your balance, rate, years remaining, and an extra monthly amount to find your new payoff date and the interest you would save.
✓ Updated July 2026Formula-basedNo signupNothing stored
The calculator finds your scheduled monthly payment from the balance, rate, and years remaining using the standard amortization formula. It then simulates the loan month by month two ways: with the scheduled payment only, and with your extra amount added on top. Because every extra dollar reduces principal immediately, less interest accrues each later month, so the loan reaches zero sooner. The gap between the two payoff dates is your time saved, and the gap in total interest is your interest saved.
No. On a standard fixed mortgage they shorten the term instead. Your required payment stays the same, but you reach a zero balance earlier. A lender recast is a separate option that can lower the payment.
No. It models only loan principal and interest. Your real monthly bill may also include escrow for property tax, homeowners insurance, and any mortgage insurance, which extra principal does not change.
Money used for extra principal is no longer liquid. Make sure you have an emergency fund and no higher-interest debt first, and confirm your loan has no prepayment penalty.
Paying extra gives a guaranteed return equal to your mortgage rate, which is appealing when rates are high. Investing may earn more on average but carries risk. This tool only shows the payoff side.
The calculator assumes a fixed rate. With an adjustable-rate mortgage the payment and payoff date can change at each reset, so treat the result as a snapshot at today's rate.
Disclaimer: This tool provides an estimate for general informational purposes only and is not financial advice. It assumes a fixed rate, equal payments, and that extra amounts apply to principal with no prepayment penalty. Confirm your real figures and prepayment terms with your lender.
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