This debt payoff calculator simulates one fixed-rate balance month by month, including optional extra payments and a smaller final payment.
Finance
Debt Payoff Calculator
Estimate payoff time and total interest from a balance, rate, and monthly payment.
Calculator
About this calculator
Formula notes
monthly rate = APR / 12; each month interest = remaining balance × monthly rate, then new balance = balance + interest − payment.
Worked examples
- Example: a 1,200 balance at 0% with a 100 monthly payment takes exactly 12 months and 1,200 total paid.
- A 25,000 balance at 19.99% APR with a 1,000 monthly payment is cleared much sooner than with 700, and the calculator quantifies the avoided interest month by month.
How to use it
- Enter the current balance and annual rate.
- Enter the regular and extra monthly payments.
- Compare payoff months and total interest after changing the extra payment.
Frequently asked questions
Why does the calculator reject a small payment?
If the payment does not exceed first-month interest, the modeled balance never declines and cannot be paid off.
Does the last payment equal the normal payment?
Usually not. The simulation reduces the last payment to the exact remaining balance plus that month's interest.
Limits and interpretation
- The schedule assumes a fixed APR, one payment every month, no new borrowing, no fees, and interest compounded monthly on the remaining balance.
- Lenders may use daily balances, promotional rates, penalty APRs, minimum-payment formulas, prepayment rules, or statement timing that changes the actual payoff.