Debt Snowball Calculator - Smallest-Balance Payoff

The debt snowball method ranks accounts from the smallest balance to the largest, regardless of APR. You pay minimums on everything and throw every extra dollar at the smallest bill. When that account closes, its payment rolls onto the next smallest. The psychological win of a closed account is the point. The debt snowball calculator estimates how many months the current smallest target takes when you combine its minimum with extra cash, which is the first chip in the snowball. Payoff months use n = −ln(1 − B × r / P) / ln(1 + r), rounded up, with r = APR / 1,200 and P = minimum + extra. If P is not larger than monthly interest, the balance never falls. $5,000 at 18% with $150 minimum and $50 extra ($200 total) takes 32 months. $2,000 at 20% with $100 + $50 takes 16 months. $10,000 at 15% with $300 + $100 takes 31 months. Snowball usually costs more interest than avalanche, which ranks by rate. People still choose snowball when a stack of small medical bills or store cards is demoralizing. Use the month count to pick a first target you can actually finish, then add that account’s former payment to extra on the next run. That roll-forward is the “snowball”; a single run does not model the whole stack. Credit-card minimums often shrink as the balance falls. Entering today’s minimum plus a fixed extra is a snapshot. If you will keep paying the same dollar amount after the minimum drops, the real payoff is faster. Penalty APRs, late fees, and new charges are not included. Do not use the extra field for a one-time lump sum unless you will repeat it every month. Recalculate after each account is paid, after a rate change, and whenever extra cash changes. Compare the first-target month count with an avalanche run on the highest APR if you want a cost check. The debt snowball calculator will not sort your accounts; list them by balance yourself, then use the months figure as the plan for the current smallest bill.