How the snowball vs avalanche calculator works
What each strategy actually is
Avalanche throws every spare dollar at the highest-APR debt while paying minimums elsewhere — mathematically optimal because it kills the most expensive interest first. Snowball attacks the smallest balance first, retire it fast, and rolls its payment into the next. The math favors avalanche; human psychology often favors snowball.
How we simulate it
Both plans are run month by month: interest accrues on every open balance, minimums (2% of balance, $25 floor) are paid first, and the entire leftover goes to the strategy's target debt. That matches how real payoff calendars behave, including the "free" month after a debt closes.
When snowball genuinely wins
If the smaller debt can be retired within a couple of months, the cash flow relief is real — one fewer minimum payment, forever. And behavioral research keeps finding that people who see an early win are far more likely to finish. A plan you abandon saves $0.