Debt Snowball Calculator
Months to pay off your smallest debt first with the snowball method.
Input sheet
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The debt snowball pays off your smallest balance first, then rolls that freed-up payment onto the next debt. This shows how long the first, smallest debt takes to clear under that plan.
How it works
Pays the smallest balance first at your total snowball payment; when it clears, the freed-up payment rolls onto the next debt.
The snowball method prioritizes psychological wins over pure math: by knocking out the smallest balance first, you get a quick, motivating victory and one fewer bill. This tool calculates the months to clear that smallest debt at your total snowball payment, after which the payment 'rolls' onto the next-smallest balance.
As with any payoff, if your payment is below the debt's monthly interest, it can't make progress — the calculator catches that case. The alternative 'avalanche' method targets the highest interest rate first, which costs slightly less overall but lacks the early momentum that keeps many people going.
Months to clear = −ln(1 − (monthly rate × balance) ÷ payment) ÷ ln(1 + monthly rate), where monthly rate = APR ÷ 12
Worked examples
$1,200 smallest debt at 18% APR, $300/month total snowball payment → ≈ 5 months to clear this debt
Throwing the full $300/month at the $1,200 balance clears it in about five months; that $300 then rolls onto the next debt.
Tips & gotchas
- List every debt smallest to largest, pay minimums on all of them, and throw every spare dollar at the smallest — that's the snowball in practice.
- When the smallest clears, don't reabsorb its payment into spending; roll it onto the next debt to keep the snowball growing.
- If staying motivated isn't your problem and saving money is, consider the avalanche method (highest APR first) — it costs a bit less in total interest.
- Stop adding new debt while you're paying down — a snowball can't roll uphill against fresh charges.
FAQ
Snowball or avalanche — which is better?
Avalanche (highest interest first) saves the most money mathematically. Snowball (smallest balance first) delivers faster psychological wins and a higher completion rate. The best method is the one you'll actually stick with.
What does 'total snowball payment' mean?
It's the entire amount you're devoting to debt payoff each month — the minimum on the target debt plus every extra dollar you can free up. As debts clear, this same total rolls forward.
What if my payment doesn't cover the interest?
Then the balance won't fall and the method stalls on that debt. You'll need to raise the payment or lower the rate (for example, via a balance transfer) before progress is possible.
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