What each method is
Avalanche: list every debt by interest rate, highest first. Pay the minimum on all of them, throw every extra dollar at the top of the list. Move to the next when one is gone.
Snowball: list every debt by balance, smallest first. Pay the minimum on all of them, throw every extra dollar at the smallest. The early wins are the point, quick payoffs build momentum.
The math (with real numbers)
Three debts: $1,000 at 8%, $4,000 at 22%, $9,000 at 14%. Extra $300/month. Avalanche kills the 22% card first (saves the most interest), then 14%, then 8%. Snowball kills the $1,000 first (one fewer payment), then 22%, then 14%.
Over a typical payoff window, avalanche saves $400–$1,200 in interest depending on the gap between rates. Snowball costs that much in interest, but lands the first payoff months earlier, which is why people stick with it.
Pick avalanche when…
- Your highest-rate debt is more than 5 percentage points above the others, the gap pays for the patience.
- You're disciplined enough to stay motivated without quick wins.
- Your debts are similar in size and the snowball-style 'first win' would happen anyway.
Pick snowball when…
- You've started and stopped debt payoff before, momentum is the missing variable.
- One small balance can be killed in 1–3 months, the visible progress fuels the rest.
- Your rates are clustered (e.g. all between 18–24%) so the math difference is small.
The hybrid: 'avalalanche'
Many advisors now recommend a hybrid, knock out one tiny debt first for the win, then switch to avalanche for the rest. Captures most of the math advantage and most of the psychological advantage.
Works well for households with one obvious 'easy kill' (a small medical bill, a $400 store card) plus a few real-money credit-card balances.
What both methods have in common
- Pay minimums on every debt every month, never miss one and trigger fees or rate hikes.
- Every dollar above minimums goes to one debt at a time, never split extras across multiple debts.
- When a debt is killed, roll its full payment into the next debt's payment (the 'snowball' compounding effect, which both methods use).
- Pause new debt entirely while paying off, extra borrowing during payoff guarantees the project never finishes.
When neither method is the right answer
Debts above 30% APR (some store cards, payday loans): consolidate first, then apply a method.
Federal student loans: don't pay extra above the avalanche threshold without considering income-driven repayment and forgiveness alternatives.
Mortgage and low-rate auto loans (<6%): typically excluded from avalanche/snowball because the math favors investing the spare dollars instead.
