List your debts, add any extra monthly payment, and see both payoff strategies side by side — months to debt-free, total interest, payoff order, and a balance chart. Pre-filled with example debts so you can try it instantly.
Edit any number — results update instantly. Both methods pay every minimum, then attack one debt with all extra money (snowball: smallest balance; avalanche: highest APR).
When a debt is cleared, its old minimum rolls into this extra amount automatically under both methods.
Each simulated month, every debt accrues interest (balance × APR ÷ 12), receives its minimum payment, and then your full extra amount — plus any minimums freed by already-cleared debts — goes to the single target debt. Snowball targets the smallest current balance; avalanche targets the highest APR. Your total monthly outlay stays the same under both: all minimums plus your extra.
Because the budget is identical, the methods differ only in order — which changes how long expensive balances survive, and therefore total interest. Simulations run month by month and stop at 1,200 months (100 years); if payments cannot outpace interest, you will see a warning instead of a debt-free date.
Both methods pay the minimum on every debt and throw all extra money at one target debt. Snowball targets the smallest balance first for quick wins and motivation. Avalanche targets the highest APR first, which minimizes total interest paid. When a debt is cleared, its payment rolls into the next target under both methods.
Avalanche (highest interest rate first) always costs the same or less in total interest than snowball, because expensive debt shrinks sooner. Snowball can still be the better choice if early wins keep you motivated — the best plan is the one you will actually stick with. This calculator shows the exact dollar difference for your debts.
Any consistent extra amount helps, because every extra dollar goes to principal on the target debt. Try different extra amounts in the calculator: even $100–$300 extra per month typically cuts months or years off the payoff and saves substantial interest. Keep a small emergency buffer first so new surprises do not go back on a card.
It rolls forward. The minimum payment from the cleared debt joins your extra payment against the next target debt, so your attack payment grows over time — that rolling effect is why the snowball method got its name. The avalanche method rolls payments the same way; only the target order differs.
If a debt's minimum payment is less than the monthly interest it accrues, its balance grows until it becomes the target debt and receives the extra payment. If your total payments never outpace total interest, the debts cannot be cleared — the calculator flags this instead of simulating forever (simulations are capped at 1,200 months).