Free debt payoff calculator
Enter your balance, rate and monthly payment to see your payoff date, the total interest you will pay, and exactly how much an extra payment each month saves you. Everything stays in your browser.
The Debt Payoff & Budget Spreadsheet pack is on the way: a snowball vs avalanche planner, a monthly budget template, and a payoff tracker to keep you on schedule.
Every month, interest is charged on whatever you still owe. We work it out as your annual rate divided by twelve, applied to the balance. Whatever is left of your payment after that interest goes to principal, the actual amount you borrowed. So early on, more of your payment is eaten by interest, and later, as the balance shrinks, more of it knocks down the principal.
This calculator simulates that month by month for an exact answer, rather than using a rough formula. The final month only pays off the small remainder, so you are never overcharged.
The catch: if your payment is smaller than the monthly interest, the balance grows instead of shrinking and the debt never clears. That is why an extra payment matters so much. Because it goes straight to principal, even a small amount each month can cut years off the timeline and save a large chunk of interest. The extra payment impact line shows you exactly how much.