Two debts share one extra payment. Each debt’s minimum is spread as a flat amount over 36 months plus interest, using the balance and rate you enter. Snowball sends the extra dollar to the smaller balance first. Avalanche sends it to the higher rate first. The page walks both orders month by month and shows the interest difference.
An $8,000 balance at 24.5% and a $2,500 balance at 11.5%, with $300 extra, do not finish on the same month or at the same interest cost. Avalanche puts the extra onto the 24.5% balance first. Snowball puts it onto the $2,500 balance first. The form shows both.
A third debt is not included. Minimum payments in real contracts are often a percent of the balance, not a 36-month flat amount. The comparison uses the two balances on the form.