Debt Avalanche Calculator

Calculate how long it takes to pay off multiple debts using the avalanche method (paying highest interest first). Compare total interest paid and time to freedom.

This calculator pays minimums on every entered debt each month, then routes all Extra Monthly Payment toward whichever unpaid debt currently carries the highest interest rate — highest-rate-first is the textbook Avalanche method, and mathematically the version that minimizes total interest paid, unlike the Debt Snowball approach's smallest-balance-first ordering. Note that this engine does NOT roll a paid-off debt's minimum payment into the extra-payment pool (extraRemaining stays fixed at Extra Monthly Payment throughout, lines 50-56) — once a debt reaches $0 it is simply skipped, and its former minimum payment is not redirected anywhere. Debt 1 Balance dominates both Total Interest Paid (a ±10% span of about 30% of Total Interest Paid) and Savings vs Minimum Payments (about 48%) — the largest single driver of each — because at the calculator's own defaults Debt 1 already carries the highest rate (18% vs Debt 2's 12%), so it's both the first target for extra payments and the biggest balance accruing interest while it waits. Neither Debt 1 Interest Rate nor Debt 2 Interest Rate move Months to Payoff at all across a ±10% probe at these defaults — not because the payoff strategy ignores rates, but because Months to Payoff is reported as a whole number of months, and a 10% rate change here doesn't add or remove enough accrued interest to shift which month the balances actually cross zero; the same rate change clearly does move Total Interest Paid, just not the integer month count. Savings vs Minimum Payments is computed against a genuine no-extra-payment baseline run with the same debt order (lines 82-96) rather than a formula that always nets to zero by construction, so the figure reflects real dollars saved by adding Extra Monthly Payment, not an accounting identity. This calculator does not account for balance transfers, changing interest rates over the payoff period, or adding new debts mid-payoff.