Debt Snowball Calculator
Find out exactly how many months until you're debt-free using the snowball method. Enter your balances, minimum payments, and any extra cash you can throw at debt each month.
About this calculator
The debt snowball method, popularized by Dave Ramsey, works by paying minimums on all debts while directing every extra dollar at the smallest balance first. Once that debt is eliminated, its payment 'snowballs' into the next smallest, accelerating payoff. This calculator models the process by treating your combined debt as a single pool: each month it charges interest as balance × (annualRate / 12), subtracts your total payment (minimums + extra), and repeats until the balance reaches zero. The core loop is: balance = balance − (minPayment + extraPayment − balance × monthlyRate). Because freed-up minimum payments compound over time, the snowball effect dramatically shortens your payoff timeline compared to making only minimums.
How to use
Suppose you have $12,000 in total debt, combined minimum payments of $300/month, an extra $150/month available, and an average interest rate of 18%. Monthly rate = 18 / 100 / 12 = 0.015. Month 1 interest = $12,000 × 0.015 = $180. Principal paid = $300 + $150 − $180 = $270. New balance = $12,000 − $270 = $11,730. Repeat each month. The calculator loops this until the balance hits $0, revealing you'd be debt-free in approximately 37 months instead of 60+ on minimums alone.
Frequently asked questions
How does the debt snowball method differ from the debt avalanche method?
The snowball method targets your smallest balance first regardless of interest rate, giving you quick psychological wins as each small debt disappears. The avalanche method instead targets the highest interest rate first, minimizing total interest paid over time. Mathematically, avalanche almost always costs less in interest, but studies show snowball users are more likely to stay motivated and complete their payoff journey. The best method is the one you'll actually stick with.
How much faster does an extra monthly payment make the debt snowball?
Even a modest extra payment of $50–$100 per month can shave years off your payoff timeline because every extra dollar reduces the principal on which interest is calculated. As balances shrink faster, less of each subsequent payment goes to interest and more attacks principal — a compounding advantage. You can test different extra payment amounts directly in this calculator to visualize the exact number of months saved for your specific situation.
Why does the debt snowball calculator use an average interest rate instead of individual rates?
This calculator simplifies the math by treating all your debts as a single combined balance at a weighted average interest rate, making it easy to get a quick payoff estimate without entering every individual account. For a more precise projection — especially if your interest rates vary widely — you'd want to model each debt separately and recalculate after each payoff. The result here is a reliable approximation that's accurate enough for planning purposes and motivational goal-setting.