Debt Payoff Calculator
Two famous strategies, one honest comparison. List your debts, set an extra monthly payment, and see which method — avalanche or snowball — gets you debt-free first and cheapest.
Your debts
🏔️ Avalanche (highest APR first)
Total interest: —
Total paid: —
⛄ Snowball (smallest balance first)
Total interest: —
Total paid: —
Total debt remaining over time
Avalanche vs. snowball: what's the difference?
Both strategies use the same budget: pay every minimum, then throw everything extra at one target debt. When that debt dies, its whole payment rolls into the next target — a "debt snowball" of growing payments either way. The only difference is the targeting order:
- Avalanche: attack the highest interest rate first. Mathematically optimal — it minimizes total interest paid.
- Snowball: attack the smallest balance first. You kill a whole debt sooner, which many people find more motivating.
The math
Each month, every balance accrues interest (balance × APR ÷ 12), minimums are paid on all debts, and the remaining budget attacks the priority target. The simulation repeats until every balance hits zero:
payment order: all minimums → extra to target → freed payments roll to next target
Worked example
Three debts: $5,000 at 22% ($125 min), $12,000 at 7% ($250 min), $8,000 at 5.5% ($90 min), plus $300/month extra. Avalanche kills the 22% card first and finishes everything in about 3.1 years, paying roughly $3,000 in interest. Snowball costs only about $100 more here — because the smallest debt is also the highest-rate one, the two strategies nearly tie. When the smallest debt instead carries a low rate, avalanche typically saves hundreds to thousands more in interest while finishing a month or two sooner.
Caveats worth knowing
- The "best" method is the one you stick with. Studies on debt payoff behavior consistently find that the quick wins of the snowball method help more people stay the course — and a finished plan beats an abandoned optimal one.
- Minimums must cover interest. If a minimum payment is smaller than the monthly interest, that balance grows forever and no strategy works — you need a bigger payment or a negotiated rate.
- This ignores fees and penalties (late fees, annual fees) and assumes rates stay fixed. Variable-rate debts can change the math mid-plan.
- Consider the escape hatches first: 0% balance-transfer offers and negotiating a lower APR with your issuer can beat either strategy's margins.
Background: the Consumer Financial Protection Bureau publishes guides on paying down debt (consumerfinance.gov).