Use this debt avalanche calculator to decide which of up to three debts should get your extra money first: the highest APR (avalanche) or the smallest balance (snowball). Enter each balance, fixed APR, and fixed monthly minimum, plus one extra monthly amount. It assumes minimums and rates stay fixed, which many credit cards do not.
Both strategies use the same debts and the same constant monthly budget, so a change in payment order is not confused with a change in how much you pay.
Debt avalanche and snowball calculator
This calculator runs in your browser. This calculator’s code does not send, save, or track your entries. All dollar amounts are USD.
Optional example: Inputs start blank. Load example fills hypothetical figures without calculating. Examples are not current rates, quotes, or recommendations.
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What does each strategy change?
Enter a zero balance for an unused debt. Inputs start blank, and the Load example figures, which match the worked example below, are hypothetical. This is a planning model, not a substitute for a lender’s minimum-payment instructions.
| Feature | Avalanche | Snowball |
|---|---|---|
| First priority for extra money | Highest APR | Smallest opening monthly balance |
| Other active debts | Receive their fixed minimums first | Receive their fixed minimums first |
| After a debt is retired | Keep the total budget; move freed money to the next priority | Keep the total budget; move freed money to the next priority |
| What the comparison measures | Interest and time under a rate-first order | Interest and time under a balance-first order |
The CFPB describes both methods. Its archived debt-reduction post says the highest-rate method eliminates the costliest debts first, which can save money over time, while the snowball method shows progress quickly but may cost more in the long run.
That archived guidance explains a strategy, not a current product offer. Neither method in this calculator accounts for how likely someone is to stick to a plan.
How much can the debt avalanche save on three debts?
Inputs. This hypothetical example uses three debts and adds $150 extra per month.
| Debt | Balance | APR | Fixed minimum |
|---|---|---|---|
| Debt 1 | $1,000 | 12% | $50 |
| Debt 2 | $500 | 0% | $25 |
| Debt 3 | $2,000 | 18% | $75 |
Formula. The constant total is $50 + $25 + $75 + $150 = $300. First-month interest is balance × APR ÷ 12: $10 on Debt 1, $0 on Debt 2, and $30 on Debt 3.
After the minimums, avalanche sends the extra $150 to Debt 3. The first month’s ending balances are $960, $475, and $1,805. Snowball instead sends the extra to Debt 2, ending at $960, $325, and $1,955.
Both pay $300 and incur the same $40 of first-month interest. Their later interest differs as their remaining balances diverge.
| Measure | Avalanche | Snowball |
|---|---|---|
| Payoff order | Debt 3 in month 10; Debt 1 in month 12; Debt 2 in month 13 | Debt 2 in month 3; Debt 1 in month 7; Debt 3 in month 13 |
| All debts paid | 13 months | 13 months |
| Total interest | $251.67 | $330.22 |
| Total payments | $3,751.67 | $3,830.22 |
| Final payment | $151.67 | $230.22 |
Result. Avalanche saves $330.22 − $251.67 = $78.55 in this example, even though both plans finish in the same numbered month. Snowball clears its first account sooner. Those are separate outcomes, not contradictory answers.
What to check. The savings depend on keeping the full $300 available every month and on rates and minimums staying as entered. The 0% Debt 2 is last under avalanche, so confirm that a 0% rate will not end before month 13.
How does the budget roll over after a debt is paid?
The model sets the monthly budget once: sum of initial fixed minimums on debts with positive balances + extra. It does not reduce that budget when an account is paid off. The CFPB describes the same idea for the snowball method: dedicate the freed-up money to the next debt.
At each month’s start, the model ranks active debts by the chosen strategy. It adds balance × APR ÷ 1200 in interest, then pays each debt the smaller of its minimum or the amount now owed. All money left in the budget goes to the ranked debts in order, never paying a balance below zero.
If a debt needs only $10 but its scheduled minimum was $50, the unused $40 can go to another debt in the same modeled month. This assumes the accounts can be coordinated that way, despite real due dates or processing delays.
How the calculator handles inputs and rounding
Ties are broken in a fixed order. Avalanche ranks by highest APR, then the smaller opening monthly balance, then the lower debt number. Snowball ranks by smallest opening monthly balance, then the higher APR, then the lower debt number.
A zero-balance account’s entered minimum does not add to the budget. Positive starting balances must be at least $0.01. If all debts are retired, the last total payment is reduced; leftover budget is not counted as a debt payment.
The model uses equal monthly periods and month-end payments, retains internal precision, and rounds only displayed dollars. A yearly summary gives at most 50 rows per strategy, or 100 total; the last year can contain fewer than 12 months.
What do the low-payment warnings mean?
A minimum no greater than a month’s interest triggers a low-payment warning. Extra money might still make the plan work, so that warning alone does not prove failure. A separate negative-amortization warning means a debt actually grew during at least one month after its payments.
A positive balance with no payment budget cannot amortize. Other unpaid paths stop after 600 months. The tool then shows remaining debt and partial interest rather than inventing a debt-free date or a complete interest-saving figure.
When this calculator doesn’t fit
- Your card minimums change each month. Many revolving cards recalculate minimums rather than keeping them fixed. For how a declining minimum compares with a fixed payment on one card, see minimum versus fixed credit-card payments.
- Rates will change. Promotional expirations, deferred interest, and variable rates are not modeled. Update the inputs when terms change.
- You still add new charges or pay fees. New purchases, annual and late fees, and prepayment charges are excluded.
- A debt has special consequences or relief options. Collections, legal priorities, and relief programs cannot be evaluated by APR alone.
The CFPB explains that some card issuers calculate interest using a daily periodic rate, so real interest can differ from this monthly approximation.
The extra-payment amount has to come from somewhere. To size it, see the 50/30/20 budget tool, and to time it around paydays, see the biweekly paycheck bill calendar. Keeping the assumed monthly total available every month is essential to this comparison.
Quick decision checklist
- List every debt with its current balance, APR, and actual minimum from the latest statement.
- Pick an extra monthly amount you can keep paying after each debt is retired.
- Run both orders and compare total interest with how soon the first account is cleared.
- Note any promotional rate end dates and rerun the plan when a rate or minimum changes.
- Stop adding new charges to the debts in the plan so the payoff order stays meaningful.
Sources and calculation review
- CFPB: How to reduce your debt (archived, originally July 16, 2019), for the two strategies and rolling freed payments to the next debt.
- CFPB: Credit cards key terms, for APR, cardholder agreements, and daily periodic interest.
Sources checked September 28, 2026. The worked example was recalculated with an independent month-by-month check. Educational estimates, not individualized financial advice.
Prepared with AI-assisted research, drafting, and calculation checks. Not independently reviewed by a human financial professional.
