For credit cards, avalanche and snowball use the same engine: pay every minimum, then throw every extra dollar at one card until it hits zero. Avalanche targets the highest APR first (least interest). Snowball targets the smallest balance first (fastest closed account). Broader debt mix (cards + loans): Debt payoff methods.
Same cards, two orders
| Card | Balance | APR | Minimum |
|---|---|---|---|
| Store card | $700 | 27% | $35 |
| Card A | $3,400 | 22% | $95 |
| Card B | $1,600 | 19% | $50 |
You free $300/month above the $180 combined minimums ($480 total toward cards). Stop new charges while you run the plan (Budgeting basics).
Avalanche order (highest APR first)
- Store card (27%) → 2. Card A (22%) → 3. Card B (19%)
Extra $300 hits the store card first. After the store card clears, roll its minimum + extra onto Card A, then Card B.
Snowball order (smallest balance first)
- Store card ($700) → 2. Card B ($1,600) → 3. Card A ($3,400)
Same first target here by coincidence; the fork appears after the store card is gone: snowball attacks Card B next, avalanche attacks Card A.
Interest sketch (rounded teaching math)
Assume minimums stay fixed until each card is paid and the $300 extra always rides on the current target. Rough interest over the first year:
| Method | First target after store card | Approx. interest year 1 | Behavioral win |
|---|---|---|---|
| Avalanche | Card A @ 22% | Lower (more dollars kill high APR sooner) | Math optimal |
| Snowball | Card B @ 19% | Higher than avalanche on this set | Card B closes sooner for a “win” |
On this sample, avalanche usually saves tens to low hundreds of dollars of interest versus snowball over the payoff, because Card A’s 22% balance is large. If the high-APR card were tiny and a low-APR card were huge, the dollar gap would shrink and snowball’s motivation edge might matter more.
Exact amortization depends on issuer minimum formulas; rebuild the table in a spreadsheet with your APRs before you commit.
When to pick which
- Avalanche if you will stick with a spreadsheet and the APR gap is wide (example: 27% vs 14%).
- Snowball if you have quit plans before and need a closed account in 60–90 days to stay engaged.
- Either beats minimum-only forever (Minimum payment trap).
Also price cutting the APR itself (Lower credit card interest rate, Lower rate without a balance transfer) or a 0% balance transfer with a clear payoff date (Balance transfer payoff). Compare transfer fee + promo interest + any post-promo interest on the remaining balance against keeping the original APR. Finishing inside the promo window is a strong target, not a requirement for any savings; leftover balances usually switch to the go-to rate going forward rather than rewriting all past promo interest.
Checklist
- List every card: balance, APR, minimum, due date.
- Choose avalanche or snowball; write the order on paper.
- Automate minimums; schedule the extra payment the day after payday.
- When a card hits zero, roll its whole payment to the next target the same week.
- Recheck APRs after any repricing letter.
Educational only. Not credit or debt-counseling advice. Issuer minimums and APRs vary; run your own amortization before you rely on the sample dollars.