Debt Payoff Calculator Plan debt payoff with snowball vs avalanche strategies and extra payment analysis.

The simulation runs month by month: (1) Apply monthly interest to each balance (balance × APR/12). (2) Apply minimum payments to all debts. (3) Apply extra payments to the priority debt (highest rate for avalanche, lowest balance for snowball). (4) When a debt reaches $0, redirect its minimum payment + any extra to the next priority debt. The avalanche method always minimizes total interest paid. The snowball method eliminates individual debts faster, providing motivation. The difference in total interest is often smaller than expected for similarly-sized debts. The simulation caps at 600 months (50 years) as a safety limit. If minimum payments don't cover monthly interest on any debt, the balance grows — the calculator will show this scenario playing out over the maximum period.