Debt Snowball vs Avalanche Calculator

How the calculator works

Both methods use the same idea: decide on one fixed amount you will put towards your debts every month, pay the minimum on every debt, and send everything left over to a single target debt. When the target is paid off, its minimum payment does not go back into your spending. It joins the extra money and attacks the next debt, so the payment on each new target is bigger than the last. That growing payment is the "snowball".

The only difference between the two methods is the order of the targets:

• Debt snowball: smallest balance first, regardless of the interest rate.
• Debt avalanche: highest interest rate (APR) first, regardless of the balance.

The calculator runs both plans month by month with your numbers. Each month it adds interest to every balance (APR ÷ 12, rounded to the cent, the way most lenders charge), pays every minimum, and sends the rest of the budget to the current target. It also shows what would happen if you paid only the minimums and stopped paying a debt's minimum once it was cleared, which is what many people do without a plan.

Worked example: four debts, 200 extra a month

The default values are a common mix: a credit card of 3,200 at 24.9% APR (minimum 90), a store card of 600 at 17.9% (minimum 25), a personal loan of 4,800 at 11% (minimum 120) and a car loan of 8,500 at 6.5% (minimum 210). The minimums add up to 445, and with 200 extra the monthly budget is 645.

Three things stand out. First, the plan matters far more than the method: either snowball or avalanche clears everything 33 months sooner than paying minimums and saves roughly 2,840 to 2,880 in interest. Second, the avalanche saves only 41.92 more than the snowball here, because the snowball's first target (the store card) is small and gone in three months. Third, the snowball gives you a paid-off account in month 3 instead of month 13, which is the psychological win the method is built around.

What a bigger extra payment does

Raise the extra payment to 400 (budget 845) and both plans finish in 23 months: 1,572.47 interest with the snowball and 1,547.56 with the avalanche, a gap of 24.91. The second 200 a month removed seven more months and roughly 660 to 680 of interest. Finding more money for the budget usually beats any choice of order.

When the order makes a bigger difference

The gap between the methods grows when the smallest debt has a low rate and a large debt has a high rate. A small 0% medical bill of 400 (minimum 50) next to a 2,500 credit card at 22% (minimum 60), with 50 extra a month: the snowball clears the medical bill in month 4 and is debt-free in 23 months with 630.59 interest; the avalanche ignores the 0% bill until the card is gone and finishes in 22 months with 610.43. If the 0% balance were large, the snowball would delay the expensive card for much longer.

Snowball or avalanche: which should you choose?

Mathematically, the avalanche always costs the least interest, because every spare unit of money goes to the debt that is growing fastest. In practice the best method is the one you will keep following for two or three years. Research on real debt repayment has found that people who close individual accounts early are more likely to keep going, which is the case for the snowball. A sensible middle path: run both plans in the calculator, and if the avalanche saves only a small amount, choose whichever order keeps you motivated.

Tips that make either plan work

• Stop adding new debt. A payoff plan cannot keep up with a card that is still being used for everyday spending.
• Keep a small emergency fund so a car repair does not go straight back on a credit card. The savings goal calculator helps you plan it.
• Keep the budget fixed. When a debt is paid off, move its whole minimum to the next target the same month.
• Ask for a lower rate. A lower APR on the biggest card, a 0% balance transfer (watch the transfer fee and the date the promotion ends) or a cheaper consolidation loan can save more than the choice of method. Compare offers with the loan calculator.
• Use windfalls. Tax refunds, bonuses or sold items paid straight to the target debt shorten the plan.

Limits of this calculator

• Interest is charged monthly at APR ÷ 12. Credit cards often use a daily rate and statement cycles, so real balances can differ by a few cents or dollars per month.
• Minimum payments are treated as fixed amounts. Many cards set the minimum as a percentage of the balance, so the required minimum falls as you pay. Keeping your payment fixed, as the plan does, is still the right move.
• Fees, promotional rates that expire, and new purchases are not included.
• For one card on its own, the credit card payoff calculator shows the full balance month by month.

Common mistakes

• Letting the budget shrink. If the minimum of a cleared debt goes back into spending, there is no snowball, and the plan becomes "minimums only" with an extra payment.
• Entering a minimum smaller than the monthly interest. On 5,000 at 24% the interest is about 100 a month; a 50 minimum never pays it off. The calculator warns you when the overall budget cannot clear the debts.
• Typing the monthly rate in the APR field. Enter the yearly rate shown on the statement, such as 24.9, not 2.075.
• Forgetting 0% and low-rate debts. Include every debt so the payoff date is real; mark interest-free debts with 0.

Frequently asked questions

Sources

• Consumer Financial Protection Bureau (CFPB): Your Money, Your Goals toolkit, debt management tools.
• Gal, D. and McShane, B. (2012). Can Small Victories Help Win the War? Evidence from Consumer Debt Management. Journal of Marketing Research 49(4).

Last reviewed 19 October 2026. Results are estimates; see our disclaimer.