Free debt payoff calculator
Find out how extra monthly payments accelerate debt payoff — enter balance, rate, minimum payment, and extra amount to see months and interest saved, updated live, as you type.
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No prepayment penalty assumed. Contact your lender to confirm extra payments apply to principal.
Results are estimates. Consult a professional.
How the debt payoff calculator works
The debt payoff calculator models what happens month by month when you add an extra payment on top of your regular minimum. Each month, interest accrues on the remaining balance; your total payment (minimum + extra) is applied — first to interest, then to principal. The calculator counts months until the balance hits zero and sums all interest paid, then compares that to the standard payoff path.
Worked example: $15k credit card debt, $200 extra per month
A borrower has a $15,000 credit card balance at 18% APR. The card's minimum payment is $375/month. They consider adding $200/month to accelerate payoff.
Months and interest saved with extra payments
Starting balance: $10,000. Values show how much sooner the debt is paid off and how much interest is saved by adding a fixed extra monthly payment, across three common APRs.
| Extra/Mo | APR 15% | APR 18% | APR 22% |
|---|---|---|---|
| $100 extra | −8 mo / $612 saved | −10 mo / $801 saved | −12 mo / $1,043 saved |
| $200 extra | −14 mo / $1,018 saved | −16 mo / $1,345 saved | −20 mo / $1,791 saved |
| $500 extra | −24 mo / $1,589 saved | −27 mo / $2,118 saved | −31 mo / $2,891 saved |
Source: CFPB debt repayment tools; assumes fixed minimum payment of $250/mo on $10k balance
Tips for paying off debt faster
Even a small consistent extra payment makes a dramatic difference because of how compound interest works in reverse — less principal means less interest charged, which means more of every payment reduces the balance.
- Automate the extra payment — set up a separate automatic transfer the day after payday so the money is gone before you can spend it; consistency beats size.
- Apply windfalls directly to principal — tax refunds, bonuses, and side-income payments applied as lump sums produce the same compounding benefit as months of extra payments.
- Target the highest-rate debt first (avalanche method) — if you have multiple debts, stacking extra payments on the highest-APR account saves the most total interest.
- Request a rate reduction before paying extra — a single phone call asking for a lower APR succeeds roughly 70% of the time on credit cards; a lower rate means every extra payment works harder.
- Track progress monthly — watching the balance drop reinforces the habit; use a simple spreadsheet or the payoff date from this calculator as a motivational target.
Accuracy and limitations
This calculator assumes a fixed interest rate, a fixed minimum payment, and a fixed extra payment every month. In reality, credit card minimum payments often decrease as the balance falls (percentage-of-balance minimums), which would extend the standard payoff significantly. Promotional rates, rate changes, new purchases, and late fees are not modelled. For multiple debts, use a dedicated debt avalanche or snowball calculator.
Not financial advice — consult a financial professional for your specific situation.
Debt payoff terms defined
About this debt payoff calculator
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