See how much interest and time you save by paying extra on your mortgage or loan each month. Full amortization comparison — no sign-up required.
Added May 9, 2026
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Enter a value for current loan balance to see your result.
Calculates how much time and interest you save by adding a fixed extra amount to your monthly loan payment. Runs a full month-by-month amortization with and without the extra payment to find the exact payoff difference.
Payment = P · r / (1 − (1 + r)^(−n)) then iterate with extra each month
Adding $200/month to a 30-year $250k loan at 6.5% saves over $58,000 in interest and cuts the loan by roughly 5 years.
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An extra $100/month on a 5-year auto loan at 7% saves about $605 in interest and pays the car off roughly 10 months early.
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Yes — extra payments made early in a loan save significantly more interest than the same payments made later, because interest accrues on a larger remaining balance. Starting extra payments in year 1 vs year 10 can double the savings.
Most lenders do, but some may apply it to future payments instead. Always mark extra payments as 'principal reduction' in your payment instructions or log in to verify how your lender applies them.
This calculator models a consistent extra payment each month. For one-time lump-sum payments, the actual savings will be proportional but not exactly the same; use the amortization schedule tool to model specific lump-sum scenarios.
No. The extra payment is on top of your existing required monthly payment. The required payment stays fixed; only the payoff date changes.
It depends on your loan interest rate vs. expected investment returns and risk tolerance. Paying off debt is a guaranteed return equal to your interest rate; investing offers potentially higher but variable returns. Many people split the difference.