Enter your debts and any extra you can put toward payoff. The calculator shows both snowball (smallest balance first) and avalanche (highest APR first) results side-by-side.
Snowball strategy
Pay off smallest balance first.
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Avalanche strategy
Pay off highest APR first.
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Recommendation
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Worked example
Take three debts: a store card at $1,500 and 12% APR with a $40 minimum, a Visa at $3,000 and 24% APR with a $90 minimum, and an auto loan at $9,000 and 7% APR with a $250 minimum, plus $200 of extra payment each month. Every month interest accrues on each balance, all minimums are paid, then the $200 extra is thrown at one target debt until it is gone, after which its old payment rolls into the next target. The snowball method targets the smallest balance first, so it clears the store card, then the Visa, then the auto loan, finishing in 31 months with $1,768 of total interest. The avalanche method targets the highest APR first, so it attacks the 24% Visa before the store card, finishing in 30 months with $1,547 of interest. Same debts, same extra payment, but avalanche saves about $221 in interest and one month, because every extra dollar kills the most expensive balance first.
| Strategy | Payoff order | Time | Interest |
|---|---|---|---|
| Snowball | Store card, Visa, Auto | 31 months | $1,768 |
| Avalanche | Visa, Store card, Auto | 30 months | $1,547 |
| Avalanche saving | 1 month | $221 |
How it is calculated
The tool simulates your debts month by month rather than using a closed-form formula, because the order you pay them in changes the result. Each month it adds one twelfth of the APR to every balance as interest, subtracts the minimum payment from each debt, then applies your extra payment to a single target. Under snowball that target is the smallest remaining balance; under avalanche it is the highest APR. When a debt is cleared, its freed-up minimum plus the extra cascade onto the next target, which is the snowball or avalanche effect that accelerates later payoffs. Avalanche is mathematically optimal because it always retires the costliest interest first, while snowball can be easier to stick with thanks to quick early wins. When the smallest balance also happens to carry the highest rate, the two strategies coincide.