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Debt Payoff Calculator
Compare two well-known strategies for clearing several debts at once. Enter each debt's balance, rate and minimum payment, plus any extra you can put toward one at a time, and see how the snowball method (smallest balance first) compares with the avalanche method (highest rate first).
Private by design · Inputs and downloads stay in your browser
Changes the currency symbol and number format only. Amounts are not converted.
Enter up to 5 debts; leave a slot's balance at 0 if you have fewer. Both strategies always pay at least each debt's own minimum; a debt's minimum rolls into the extra pool once it is paid off.
How to use the Debt Payoff Calculator
- Enter the balance, interest rate and minimum payment for each debt you have, up to five. Leave a slot's balance at 0 if you have fewer.
- Enter any extra amount you can pay each month beyond all the minimums combined.
- Select Calculate to see the months and total interest under both the snowball and avalanche strategies.
Use the currency selector above the inputs to change the symbol. It changes the display only and does not convert amounts.
Snowball vs. avalanche
The snowball method directs every extra dollar toward the smallest balance first, then moves to the next-smallest once that one is cleared. Many people find this motivating because balances disappear quickly.
The avalanche method directs extra dollars toward the highest interest rate first instead. It minimizes the total interest paid, though the first debt it clears is not necessarily the smallest.
How the calculation works
How the comparison is calculated
Each month: interest accrues on every debt at its own rate ÷ 1200
Every debt receives at least its minimum payment
All remaining budget (extra, plus minimums freed from any already-paid-off debt) goes to the top-priority remaining debt
- Snowball priority: smallest remaining balance first.
- Avalanche priority: highest interest rate first.
Both strategies use the exact same simulation engine and the same total monthly budget; only the priority order differs, so the comparison isolates the effect of that one choice.
Debt payoff calculation example
Three debts — 500,000 at 22% (minimum 15,000), 200,000 at 18% (minimum 6,000) and 800,000 at 12% (minimum 20,000) — with an extra 20,000 a month:
| Total debt | 1,500,000 |
|---|---|
| Extra monthly payment | 20,000 |
| Snowball: months to debt-free | 30 |
|---|---|
| Snowball: total interest | 308,825.77 |
| Avalanche: months to debt-free | 30 |
| Avalanche: total interest | 298,855.59 |
Avalanche saves 9,970.18 in interest here while taking the same number of months. Amounts are shown without a currency symbol because the arithmetic is identical in any currency. The currency selector only changes the symbol and number format; it never converts amounts.
Assumptions and limitations
Assumptions
- Every debt always receives at least its own minimum payment.
- A debt's minimum payment is freed up and added to the extra pool the moment it is fully paid off.
- No new charges, promotional rates, fees or changing interest rates are modeled on any debt.
Limitations and why results can differ
- Avalanche minimizes total interest mathematically, but the difference between the two methods can be small when balances and rates are similar, as in the example above.
- Only up to 5 debts are supported.
- If a minimum payment does not even cover a debt's own monthly interest, the calculation is refused rather than modeling a balance that grows forever.
Frequently asked questions
Which method should I use?
Avalanche saves the most money in interest. Snowball can be easier to stick with because balances clear sooner. Both are shown here so you can weigh the trade-off.
What happens to a paid-off debt's minimum payment?
It is added to the pool of extra money directed at your next priority debt, so your total monthly payment stays the same throughout.
What if I have more than 5 debts?
Group smaller similar debts together, or run the calculation for your largest five and treat the rest separately.
Why did the calculator refuse to run?
A minimum payment that does not cover a debt's own monthly interest can never reduce that balance, so the calculator asks for that debt's real minimum instead.
Methodology
Each of up to 5 debt slots is validated independently: balance from 0 to 100,000,000, interest rate from 0% to 50%, and minimum payment from 0 to 10,000,000, with an unused slot left at a 0 balance. An active debt (balance above 0) is rejected if its minimum payment does not exceed its own first month's interest.
Both strategies run the identical month-by-month simulation (interest accrues on every active debt, every debt receives at least its minimum, and all remaining budget goes to the top-priority remaining debt) capped at 1,200 months as a safety limit. Only the priority rule differs: snowball sorts by smallest remaining balance, avalanche by highest interest rate. Rounding is applied only for display. The calculation runs in your browser and inputs are not sent to a server.
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Disclaimer
Results are estimates based on the assumptions you enter. Actual repayments depend on your lender’s terms, fees and rate structure. This page is for information only and is not lending or financial advice. Read the full Disclaimer.
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This tool is part of Loans and Mortgages.
A common order: check what you can afford, compare loan offers, then see how extra payments change total interest.