How the avalanche method works
Every card receives its minimum payment every month. Whatever extra you can afford goes entirely toward the card with the highest interest rate — not split evenly, not toward the smallest balance, all of it toward the card actually costing you the most. Once that card is paid off, its old payment doesn't disappear: it rolls onto the next-highest-APR card, making each payoff faster than the last.
Rewards Card $4,200 (27.49% APR), Travel Card $2,400 (24.99% APR), Cash Back Card $3,800 (21.99% APR) $150 extra/month → 30 months to debt-free, $3,506 in interest, $13,906 total paid Rewards Card carries the highest rate, so the extra $150 is directed there first. Once it is paid off, its $140 minimum payment is freed and joins the extra-payment pool for the next-highest-APR card, Travel Card. The remaining payment capacity then rolls to Cash Back Card, completing the payoff in month 30.
The expandable month-by-month schedule shows how much is paid toward each card every month, including how the available payment amount shifts to the next-highest-APR card as cards are paid off.
Why highest APR first minimizes interest
Interest is charged as a percentage of what you still owe, so a dollar sitting on a 27.49% card is costing you more every single month than that same dollar sitting on a 21.99% card. Paying down the highest-rate balance first shrinks the amount you're being charged the most on, as early as possible. Under the calculator's assumptions, directing extra payments to the highest-APR balance first minimizes total interest paid when the same total payment amount is available each month.
Frequently asked questions
Is the avalanche method always the fastest way to pay off credit cards?
The avalanche method minimizes total interest for a given payment plan, and it will often result in an earlier overall debt-free date as well. The snowball method can sometimes feel faster because it eliminates smaller balances sooner, even when the overall debt takes longer to repay.
What happens if I don't have any extra to put toward payoff?
Leave Extra Monthly Payment at $0 and the calculator still works — it shows how long payoff takes and how much interest accrues making only the minimum payment on every card, which is often a useful (if sobering) number to see on its own.
How is this different from the Debt Avalanche Calculator?
Same underlying avalanche math, applied specifically to credit cards, with a simpler, more focused calculator: no snowball toggle and no advanced options like annual raises or one-time payments. If you want to compare avalanche against snowball, or model a scenario with those extras, the Debt Avalanche Calculator covers any kind of debt (not just credit cards) with that fuller feature set.
Does this calculator store my data?
No. All calculations run in your browser. Nothing you enter is sent to a server or saved anywhere.