Debt Payoff Calculator
Compare multi-debt payoff plans using avalanche (highest APR first) or snowball (lowest balance first) strategies under a fixed monthly payment budget. Neither strategy is universally best. Avalanche generally prioritizes interest rate; snowball prioritizes balance size. Actual creditor payment rules may differ.
Your results will appear here
Enter your assumptions and calculate to see the estimated result and supporting details.
How this calculator works
Enter one or more debts with optional names, balances, APRs, and minimum payments, plus any extra monthly payment and a strategy.
The calculator keeps a fixed monthly debt budget equal to the sum of original minimum payments plus extra payment. When a debt is paid off, that former minimum automatically accelerates remaining debts.
Primary result is estimated debt-free time. Secondary results include total interest, total paid, payoff order, and an annual summary. A full monthly timeline is optional and collapsed by default.
Formula / methodology
monthlyBudget = Σ original minimums + extra monthly interest = balance × (APR / 12) apply mins → allocate leftover by strategy → cascade same month
- Interest and payments use cents rounding consistent with the site’s debt infrastructure.
- Avalanche order: highest APR → lower outstanding balance → stable input order.
- Snowball order: lowest outstanding balance → higher APR → stable input order.
- Search horizon is 1,200 months (100 years).
Worked example
Debt A $5,000 at 20% APR with $150 minimum; Debt B $3,000 at 10% APR with $100 minimum; $100 extra (fixed budget $350).
Avalanche: about 28 months and $1,569.60 total interest. Snowball: about 29 months and $1,835.46 total interest under this cents-rounded monthly model.
Important assumptions
- APR is modeled monthly as APR ÷ 12 — not daily issuer math.
- Fees, promotional APR, penalty APR, and changing minimum-payment formulas are not modeled unless entered.
- Results are estimates for educational use only.
Common questions
Not always. Avalanche often reduces total interest when APRs differ, but snowball can clear smaller balances sooner. Choose based on your goals; this tool does not give personalized advice.
The monthly budget stays fixed. Money that had covered that debt’s minimum becomes available to accelerate remaining debts.
Issuers may use daily balances, different posting dates, fees, or minimum formulas. This calculator uses a simplified monthly model.
Yes. As long as the overall monthly budget (other minimums plus extra) is positive, remaining money can still be allocated by strategy.