How debt payoff plans work
Every month you pay the minimum on each debt, and any extra goes to one target debt. With rollover on, when a debt is paid off its payment moves to the next target, so your total monthly payment stays the same while the debts disappear faster and faster. Turn it off to see what happens if you stop paying that money toward debt instead.
The avalanche method targets the highest interest rate first, which always costs the least interest. The snowball method targets the smallest balance first, which costs a little more but pays off whole debts sooner, and many people find that easier to stick with. The savings compare your plan with paying only each debt's own minimum, with no extra and nothing rolled over. Interest is calculated monthly, and real minimum payments on credit cards may shrink as the balance drops.