How the debt avalanche method works
The debt avalanche method is the mathematically optimal way to pay off multiple credit cards. Instead of ordering your cards by balance, you order them by APR, highest to lowest. You keep paying the minimum on every card, but every extra dollar you can put toward debt goes to the card charging you the most interest. Once that card is cleared, its minimum payment joins the extra pool attacking the card with the next-highest rate — and so on, until every card is paid off.
Because interest compounds fastest on your highest-rate balances, eliminating that rate first means less of your future payments get eaten by interest — which is why, dollar for dollar, avalanche beats every other ordering strategy for minimizing total interest paid.
How this calculator works
Enter each of your cards with its balance, APR, and minimum payment, plus how much extra you can pay across all cards combined each month. The calculator pays every card's minimum, directs 100% of your extra payment at whichever remaining card has the highest APR, and reassigns that card's minimum to the extra pool the instant it reaches zero — continuing until all balances are cleared.
A worked example
Using the same three cards as our snowball example — a $1,200 store card at 26.99% APR, a $4,500 Visa at 21.99% APR, and a $2,800 Mastercard at 18.99% APR — the avalanche method targets the store card first, not because it's the smallest, but because it carries the highest rate. Compared to the snowball ordering on this same set of cards, the total interest paid across all three cards is typically somewhat lower with avalanche, because the highest- rate balance stops accruing interest sooner.
Making avalanche work for you
- List your cards in order of APR before you start — the highest rate is always your first target, regardless of balance size.
- If a high-APR card also has a large balance, expect it to take a while before you see your first full payoff — that's normal, and the interest savings are still adding up in the background.
- Prefer quicker visible progress instead? Compare against the Debt Snowball Calculator, which orders by balance instead of rate.
- A high enough APR on one card might make a balance transfer worth exploring before committing to a long avalanche payoff.