Debt snowball vs avalanche: compare your payoff plan
Model several balances with their own annual rates and minimum payments. Keep the same total monthly debt budget when comparing the two allocation methods.
Model checked: 9 November 2026 · Best Finance Calc
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Two priorities, one monthly budget
Snowball directs available extra money to the smallest remaining balance. Avalanche directs it to the highest annual rate. This model first accrues monthly interest, pays each active debt's minimum where possible, then allocates the remaining budget by the selected priority. It keeps the original combined minimum payments plus your extra as a constant monthly pool, so money from a cleared debt can continue paying the others.
Worked example with a US$300 monthly pool
Debt A has a US$1,000 balance at 8% nominal annual interest and a US$50 minimum. Debt B has US$5,000 at 24% and a US$150 minimum. Add US$100 monthly extra: the total budget is US$300. In this site's simplified monthly model, both methods finish in 26 months. Avalanche produces US$1,518.25 total interest; snowball produces US$1,655.95. The same rounded payoff month can hide an interest difference of US$137.71. The final payment is capped at what remains due.
Compare results without changing the assumptions
Enter the same balances, rates, minimums and extra for both runs. Record the modeled months and total interest, and save each version in a separate named study. Changing the total budget while switching methods makes it impossible to attribute the result to the payment order alone. The debt engine supports up to 30 balances; the dedicated Excel debt workbook has its own smaller input limit shown in its guide.
Understand the simplified interest model
Interest is applied once per month using the annual nominal rate divided by 12. This is not an exact credit-card statement simulator. It does not model grace periods, daily average balances, promotional expiry, future fees or changing percentage-based minimums automatically. The forecast runs for at most 1,200 months and rejects plans that do not finish within that horizon.
Use the result as a planning comparison
The model ranks amounts and rates; it does not prioritize secured debts, arrears, legal obligations or urgent household needs. Those can change which payment deserves attention in real life. Review your contracts and your cash reserve before acting. No method shown here is a personalized recommendation or a guarantee of the lender's posting rules.
Questions about this model
Can the payoff month be the same but the cost differ?
Yes. Compare total interest and the final partial payment as well as the number of months.
Does this calculate my exact credit-card bill?
No. It uses a simplified monthly-interest model, not the daily-balance and fee rules of every card agreement.
Model and reference material
Educational estimates, not a credit offer or personal financial advice. The examples use stated assumptions and the site’s documented engine.