Debt payoff calculator
Enter your total debt, average interest rate, and monthly payment amount. The result compares snowball vs avalanche payoff timelines and total interest paid under each method.
Debt-free timeline
52 months
Snowball method
52 months
$6,200 total interest
Avalanche method
50 months
$5,800 total interest
Save $400 with avalanche
Based on $25,000 debt at 18% average rate with a $600 monthly payment.
How it works
n = −ln(1 − (r × B) / P) / ln(1 + r)
Where n = months to payoff, r = monthly interest rate, B = balance, P = monthly payment. The snowball method assumes you pay minimums on all debts except the smallest (which gets extra). The avalanche method targets the highest-rate debt first. With a single average rate, results are approximate — they improve with more detailed debt data.