Debt Payoff Calculator
Compare the avalanche and snowball methods to clear multiple debts faster.
Results update as you type.
About this calculator
This debt payoff calculator plans how to clear several debts at once using either the avalanche method (target the highest interest rate first) or the snowball method (target the smallest balance first). You pay the minimum on every debt and throw any extra payment at the current target; when a debt is cleared, its whole payment rolls onto the next one.
It simulates the plan month by month, charging interest and applying payments until every balance hits zero, then reports the months to debt-free, the total interest, and the order debts fall. For example, with a 5,000 card at 22%, a 12,000 loan at 7% and a 3,000 debt at 15%, the avalanche method attacks the 22% card first because it bleeds the most interest, while snowball would clear the 3,000 balance first for an early win.
Use it to choose a strategy, to see how much sooner an extra monthly payment makes you debt-free, and to compare the interest cost of avalanche versus snowball. Avalanche always costs the least mathematically; snowball trades a little extra interest for motivating quick wins.
Frequently asked questions
Avalanche or snowball — which is better?
The avalanche method (highest APR first) always costs the least interest and clears debt fastest mathematically. The snowball method (smallest balance first) costs a little more but delivers quick wins that many people find easier to stick with.
Why does the extra payment matter so much?
Minimum payments are mostly interest early on, so progress is slow. Every extra dollar goes straight to principal on the target debt, and once that debt is gone its whole payment rolls onto the next — snowballing your firepower.
How does the debt snowball method work?
You order debts from smallest balance to largest, pay minimums on all of them, and put every spare dollar on the smallest. When it clears, its payment joins the minimum on the next-smallest, so the amount attacking each debt grows as you go.
How does the debt avalanche method work?
You order debts by interest rate, highest first, paying minimums everywhere and directing extra money to the highest-rate debt. Because it kills the most expensive interest soonest, avalanche clears the total debt for the least interest and usually the fewest months.
How much faster does an extra payment clear my debts?
A lot, because minimums are mostly interest early on. Raising the extra monthly payment sends more straight to principal on the target debt and, via the rollover effect, accelerates every debt after it — enter different extra amounts to see the months saved.
Can I add more than three debts?
This calculator models up to three debts, which covers most households’ credit cards and loans. If you have more, group similar-rate balances together or focus on your three largest to plan the payoff order.
API — use this calculator from code
Call this calculator as a free JSON endpoint — no key required. Send the field values below as query parameters or JSON. Read the full API docs →
Endpoint
GET https://calculator.free/api/v1/debt-payoff/curl
curl "https://calculator.free/api/v1/debt-payoff/?mode=avalanche&extra=200&bal1=5000&apr1=22&min1=100"JavaScript fetch()
const r = await fetch(
"https://calculator.free/api/v1/debt-payoff/?" + new URLSearchParams({
"mode": "avalanche",
"extra": "200",
"bal1": "5000",
"apr1": "22",
"min1": "100"
}));
const data = await r.json();
console.log(data.results);Results are estimates for general guidance only, not financial, medical or tax advice.