Debt Snowball Calculator

What this result means

The estimate answers a narrow question: if the balances, APRs, required monthly payments, and extra amount you entered stayed the same, and you made no new charges, how would this snowball model apply extra money, when would each listed debt reach $0, and how much interest would it add along the way?

Starting values on the form are examples you can change. They are not a recommendation and are not presented as typical U.S. debts or rates. FinanceAvatar does not fetch or display current APRs.

This is not a minimum-payment calculator. You type each debt’s required payment. The model does not replace that amount with an issuer formula. Credit-card agreements often set a minimum due that can change with the balance; this page does not recreate that formula.

How the snowball calculation works

Each unpaid debt uses the same monthly-rate interest model as the Credit Card Payoff Calculator: a monthly rate of APR ÷ 12, applied once to the remaining principal, with interest rounded to the nearest cent. Amounts are tracked in cents.

For every month, the model first applies each unpaid debt’s required payment, not more than the amount owed that month (principal plus that month’s interest). If a required payment is larger than the remaining owed amount, the leftover is added to the extra pool the same month. The extra pool also includes the shared additional monthly amount plus the required payments of debts already paid off.

That extra pool is then applied to unpaid debts in snowball order: smallest remaining principal at the start of the month first. If that extra pays a debt off, leftover funds continue down the list in the same month. The last payment on a debt is reduced so the balance finishes at exactly $0.

If the APR is 0%, no interest is added and payments reduce principal only, aside from the same last-payment rounding.

Payoff-order and tie-breaking rules

Extra money is directed to the unpaid debt with the smallest remaining principal at the start of the month. Remaining principal is the current modeled balance before that month’s interest and payments. The ranking is recomputed each month, so a debt can become the target after another balance falls.

If two remaining balances are equal, extra payment goes to the debt that appears first in your list. APR is not used to break a snowball tie. Debts that reach $0 in the same month are listed in that same order.

When a required payment cannot amortize a debt

If a debt’s required payment is less than or equal to the interest added in a month, that balance does not fall until it receives extra snowball funds. The calculator flags those debts. It still runs the full snowball model; it does not invent a payoff date from the required payment alone.

If extra money and freed required payments are never enough for every remaining debt to shrink, the model stops and reports that the budget does not pay off every debt. A 600-month cap exists only as a safety stop. Hitting that cap is reported as not paid off, not as a 50-year payoff.

Avalanche comparison

The comparison keeps every balance, APR, required payment, and the extra amount the same. The only change is payoff priority: extra goes to the highest APR first. If two APRs are equal, extra goes to the debt listed first. The page shows the modeled months, interest, and amounts paid, and the numerical differences. It does not label either strategy better.

The CFPB’s debt action plan describes paying smallest debts first and paying highest interest rates first as two basic strategies, and states that one strategy isn’t better than the other. That is an educational description of the CFPB material, not a recommendation from FinanceAvatar.

APR versus issuer interest calculations

The CFPB describes APR as the yearly rate typically used to state a card’s interest. This calculator converts that yearly rate to a monthly rate by dividing by 12.

Many issuers instead use a daily periodic rate and an average daily balance. The CFPB explains that a daily periodic rate is often APR ÷ 360 or APR ÷ 365. Because this page does not model those daily methods, a statement can show a different interest charge even at the same APR.

What the calculator does not include

• New purchases, cash advances, or balance transfers
• Annual fees, late fees, or other account fees
• Penalty APRs or promotional-rate expiration
• Grace periods or multiple APR buckets on one account
• Issuer-specific daily or average-daily-balance methods
• An issuer’s contractual minimum-payment formula
• Collection costs, bankruptcy, or settlement

Assumptions and limitations

• Each APR you enter does not change over the payoff.
• Payments are monthly and applied after that month’s interest.
• No new charges are added to any balance.
• Currency amounts are rounded to the nearest cent. The final payment on a debt is reduced so the remaining balance is $0.
• Required payments you enter stay the same until that debt is paid off. They are not recalculated as the balance falls.
• A 600-month cap exists only as a safety stop for the simulator.