Plan a loan payment or find out when your balance could be paid off. Compare a set loan term with a fixed monthly payment, and see how extra principal can change the payoff timeline and interest cost.
Fixed-term payment • Fixed-payment payoff • Optional extra monthly principalLoan cost and payoff comparison
Remaining balance
Blue: regular payments only. Green dashed: with extra monthly principal.
| Measure | Regular payments | With extra |
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Amortization schedule
| Period | Regular payment | Extra principal | Interest | Ending balance |
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How to use the payment calculator
Choose whether you want to estimate the monthly payment for a fixed term or find the payoff time for a payment amount you already know. Enter the loan amount and annual interest rate. In fixed-term mode, enter years and any additional months. In fixed-payment mode, enter your regular monthly payment. Turn on extra principal to compare a faster payoff.
How fixed monthly payments work
Each monthly payment first covers interest accrued on the current balance. The rest reduces the principal. As the balance declines, the interest portion generally gets smaller and more of each payment goes toward principal. An extra principal payment can reduce the balance sooner and lower the interest paid over time.
View the payment formula
For principal P, monthly interest rate r, and n payments, the fixed payment is P × r ÷ [1 − (1 + r)−n]. At 0% interest, the payment is P ÷ n. In fixed-payment mode, the schedule is calculated month by month until the loan is paid, or flagged if the payment cannot cover monthly interest.
Questions and limitations
Does this include fees, insurance, or taxes?
No. It estimates principal and interest only. Add-on fees, insurance, taxes, variable rates, and lender-specific payment rules can change the actual amount due.
Can a fixed payment fail to pay off the loan?
Yes. If the payment is less than or equal to the interest accruing each month, the balance will not decline. The calculator will report that the payment is insufficient.
Is this designed for mortgages or car loans?
The fixed-rate math can estimate many installment loans. For full housing costs or vehicle-specific details, use the Mortgage Calculator or Auto Loan Calculator.
Results are estimates for general information. Check your loan agreement for the exact payment schedule, fees, and payoff amount.