Debt Snowball Calculator

About this calculator

Enter a balance, interest rate, and fixed monthly payment and this calculator solves the standard loan amortization equation for time: n = −log(1 − rB/P) / log(1 + r), where r is the monthly interest rate, B the starting balance, and P the payment. Total interest paid is simply the sum of all payments minus the original balance.

This single-debt payoff math is the engine behind the popular debt snowball method (made famous by Dave Ramsey): list every debt smallest-balance-first, pay only the minimum on the rest, and throw every spare dollar at the smallest one until it's gone — then roll that entire payment into the next debt. Running each debt through this calculator shows exactly how many months of extra payment it takes to knock it out and free up cash for the next one.