Debt Snowball vs. Avalanche Calculator

Avalanche targets the highest-rate debt first, so it minimizes total interest. Snowball targets the smallest balance first, so it clears an entire account sooner — which behavioral research links to actually finishing. Neither is universally "better"; run both above with your real numbers and see how big the interest gap actually is for you. See Snowball vs. Avalanche for the full comparison.

Usually, but not always. Avalanche ranks debts by their current rate, so a 0% introductory promo looks like free money right now and gets deprioritized — even though the rate can jump sharply once the promo ends. If a lot of balance is still sitting there when it does, that flip can cost more than avalanche saved elsewhere, letting snowball win instead. See the methodology for exactly how promo rates are modeled.

The calculator switches that debt to its normal APR starting the very next month, and interest starts accruing on whatever balance is left — in full, with no grace period. The schedule marks the switch with a "promo expired" event so you can see exactly when it happens.

No. Everything is calculated in your browser — nothing you type is sent to a server. Your scenario is optionally saved to your own browser's storage so it's there next time, and that never leaves your device either. See the Privacy page for the full detail.

This calculator compounds interest once a month: balance × APR ÷ 12, rounded to the cent. Most card issuers instead compound daily off your average daily balance, which produces a slightly different — usually marginally higher — number. The gap is normally small but never exactly zero. See the methodology for the precise formula used here.

Yes. "Share this plan" encodes your whole scenario directly into the page's URL — nothing is uploaded anywhere. Anyone with the link can open it and see the same numbers, decoded entirely in their own browser.