This debt snowball calculator simulates both famous payoff strategies on your actual debts — smallest-balance-first (snowball) vs highest-rate-first (avalanche) — and reports months to debt-free and total interest for each, so you can choose with the price tag visible.
How the simulation runs: minimums on everything, your extra payment hammering the strategy’s target; when a debt dies, its freed minimum rolls into the next target (the “snowball”). Avalanche always wins on paper — mathematics guarantees it. Snowball exists because humans quit: behavioral research finds quick small wins raise completion rates. The best strategy is the cheaper one you will still be running in month nine — now you know each one’s price.
Two Orders, One Payment Budget — Simulated Honestly
The mechanics matter: both strategies pay identical total monthly amounts; only the order of the extra dollars differs — and when a debt dies, its minimum joins the attack fund. A single combined balance with one rate is our Debt Payoff Calculator‘s home turf; this page exists for the multi-debt ordering question. Part of our Finance Calculators collection.
Worked Example (Verified by Simulation)
- $8,000 at 22% + $3,000 at 12%, $200/mo extra (defaults): avalanche (22% first) = 34 months, $3,161 interest · snowball (small first) = 36 months, $3,825 interest — the snowball’s motivational premium here is $664 and 2 months
- When smallest = highest-rate (a $3,000 card at 22% beside an $8,000 loan at 12%), the strategies coincide exactly: 32 months, $2,063 either way — order debates vanish when rankings agree
- The premium’s shape: it grows with the rate gap and the small debt’s size; it shrinks to noise when rates are similar — compute yours before arguing about it
- Minimums trap: with $0 extra, both strategies degrade to minimum-payment purgatory (the simulation will happily show you 100+ months; card minimums near interest-only are the real enemy)
Choosing Like a Behavioral Economist
- If the interest gap is small (< ~$200 total), take the snowball’s motivation free of charge.
- If the gap is large, consider the hybrid: snowball one quick kill for momentum, then avalanche the rest.
- Whatever the order: automate minimums on everything (late fees and credit damage dwarf strategy differences).
- A balance-transfer or consolidation offer rewrites the board entirely — new rates mean new simulation; rerun this page with post-transfer numbers.
Related Tools
- Debt Payoff Calculator — single-balance payoff plans
- Credit Card Payoff Calculator — one card, exact months
- Finance Calculators — the full collection
Frequently Asked Questions
What is the debt snowball method?
Pay minimums on all debts, throw every extra dollar at the smallest balance first — regardless of rate — then roll that debt’s freed payment into the next smallest. The wins come fast and visibly, which is the point: motivation through progress. This calculator simulates it against the avalanche on your numbers.
Is snowball or avalanche better?
Mathematically avalanche (highest rate first) always costs less interest and finishes no later — in the defaults it saves $664 and 2 months. Behaviorally, studies (e.g. Kellogg School research on small victories) find snowball users more likely to eliminate debts entirely. Better = cheaper among the plans you’ll actually complete.
How does the “rolling” part work?
When a target debt is paid off, its minimum payment isn’t pocketed — it joins the extra-payment pool aimed at the next target. Your total monthly outlay stays constant while the attack amount compounds: that growth is the snowball (and the avalanche uses the identical roll; only ordering differs).
What if a minimum doesn’t cover monthly interest?
Then that debt grows despite payments (negative amortization) and no ordering fixes it — the simulation would run to its 1,200-month cap. The real fixes: raise total payment, negotiate the rate, or restructure. The calculator’s assumptions require minimums that at least dent principal.
Should I stop retirement contributions to fund the extra payment?
Generally keep any employer match (an instant 100% return beats a 22% APR), then aim extra cash at high-rate debt before unmatched investing — the guaranteed “return” of killing a 22% balance is 22% after tax, which few investments promise. Individual situations vary; the Emergency Fund Calculator’s buffer comes first so new shocks don’t re-load the cards.
Is this debt snowball calculator free?
Yes — free, instant, no sign-up.