How snowball and avalanche are calculated here
Both methods use the same debts, the same APRs, and the same extra payment. Minimums are paid on every balance. Snowball throws all extra dollars at the smallest balance first, then rolls that payment into the next-smallest. Avalanche throws extra at the highest APR first. We run both until the last balance hits zero and compare months and total interest.
Avalanche usually costs less interest. Snowball often feels faster because a small card vanishes first. If motivation is the bottleneck, snowball can still be the rational household choice — an unpaid plan that looks optimal on paper is worse than a plan you keep. The gap between methods shrinks when the extra payment is large relative to the balances.
This page assumes fixed APRs and no new charges. Issuers can reprice, add fees, or change minimums. If you have one card only, the credit-card payoff calculator is simpler. The strategy guide explains when a balance transfer is a third option — and when the transfer fee eats the teaser.