Debt Payoff Calculator (Snowball vs. Avalanche)
List your debts, add whatever extra you can put toward them each month, and see the two proven payoff strategies compared side by side: the avalanche (highest interest rate first, the mathematically cheapest) and the snowball (smallest balance first, the fastest early wins).
The calculator simulates every month — accruing interest, paying minimums, and rolling each freed-up minimum into the next target debt — so you can see exactly how many months each method takes and how much interest each one costs.
3 debts · $15,000 total · paying $530/mo
Avalanche
Highest APR first
3y 1m
until debt-free
Total interest: $4,423
Snowball
Lowest balance first
3y 4m
until debt-free
Total interest: $5,905
The avalanche method saves $1,482 in interest and pays off 3m sooner.
Payoff order
- 1Credit cardpaid off in 2y 6m
- 2Personal loanpaid off in 3y
- 3Medical billpaid off in 3y 1m
Calculation Formulas
Each month, every debt accrues interest on its current balance at its own APR before any payment is applied.
Your total monthly outlay stays fixed. Minimums are paid on every debt first; when a debt is paid off, its freed minimum stays in the budget and rolls onto the next target — which is what accelerates payoff over time.
After minimums, all remaining budget is applied to a single target debt chosen by the strategy. Avalanche minimizes total interest; snowball clears individual debts fastest.
Example:
With a 24% card, an 18% card, and a 6% loan, avalanche attacks the 24% card first; snowball attacks whichever has the smallest balance first.
Key Figures
| Figure | Value | Description |
|---|---|---|
| Avalanche | Highest APR first | Mathematically cheapest — least total interest. |
| Snowball | Lowest balance first | Fastest first payoff — behavioral momentum. |
| Freed minimums | Roll forward | A paid-off debt’s minimum is redirected to the next target. |
Note: Results are estimates for planning purposes. Rates, fees, taxes, and insurance vary by lender and location — confirm exact figures with a licensed professional before making financial decisions.
Standards & Sources
Last verified: July 2026
- CFPB debt-reduction guidance
The Consumer Financial Protection Bureau describes both the highest-rate-first and lowest-balance-first approaches as valid strategies, noting the trade-off between interest saved and motivation.
- Standard amortization simulation
Interest accrual and payment application follow standard installment-debt math, applied month by month so the comparison between strategies is exact.
How to Use This Calculator
- Add each debt with its balance, interest rate (APR), and minimum monthly payment.
- Enter any extra amount you can put toward your debts each month.
- Compare the avalanche and snowball results — months to debt-free and total interest for each.
- Pick a strategy and follow the payoff order shown; the avalanche saves the most money, the snowball delivers the first payoff soonest.
Frequently Asked Questions
What is the difference between the debt snowball and avalanche?
The avalanche method targets the debt with the highest interest rate first, which minimizes the total interest you pay. The snowball method targets the smallest balance first, which clears individual debts faster for early motivation. Both pay the same total each month; only the target order differs.
Which debt payoff method is better?
The avalanche always costs the least in total interest and usually clears all debt at least as fast. The snowball can be worth a small extra cost if the quick early wins keep you motivated to stick with the plan. This calculator shows both so you can weigh the interest difference against the behavioral benefit.
How does adding extra payment change things?
Every extra dollar goes to your target debt after minimums are covered, and once a debt is paid off its minimum rolls into the next target — so the extra amount compounds in effect. Even a modest extra monthly payment can cut months or years off your debt-free date.
What is a minimum payment and why does it matter here?
The minimum payment is the smallest amount a lender requires each month. The calculator pays every debt’s minimum first, then applies the remainder to the target. If a debt’s minimum is lower than its monthly interest, that balance grows until the strategy targets it — a sign that debt needs priority.
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