About the Debt Avalanche Calculator
With the debt avalanche method, you pay the minimum on every debt and direct any extra money to the debt with the highest APR. Once it is paid off, that payment moves to the debt with the next-highest rate.
Enter your debts to see your estimated payoff time, debt-free date, total interest, and payoff order, plus the snowball method's numbers with the same payments for comparison.
How It Works
Each month, interest is added to every balance at its APR ÷ 12. Every debt receives its minimum payment, and the rest of your monthly budget goes to the debt with the highest APR (ties go to the smaller balance).
When a debt is paid off, your monthly budget stays the same and the freed-up payment is applied to the next-highest-rate debt until every balance is $0.
Formula
Example
Three debts — Credit card A: $3,000 at 24.99% ($90 minimum), Car loan: $12,000 at 6.5% ($280), Credit card B: $800 at 19.99% ($35) — plus $200 extra per month.
Inputs
- Total balance
- $15,800
- Minimums
- $405/mo
- Extra payment
- $200/mo
Results
- Avalanche payoff time
- 2 years, 5 months
- Avalanche total interest
- $1,741.49
- Snowball (same payments)
- $1,776.69
- Saved vs. minimums only
- $2,338.84
Both methods use the same monthly budget; only the order of focus payments changes. Interest saved is compared with paying only each debt's minimum without rolling payments over.
Assumptions & Limitations
- Fixed APRs and minimum payments; real minimum payments on credit cards usually fall as balances fall.
- No new charges on any account during payoff.
- Interest is charged monthly at APR ÷ 12; lenders may use daily balances.
- Payments rolled over: when a debt is paid off, its minimum is added to the next focus debt.
- Not included: fees, promotional 0% periods ending, balance transfers, and consolidation loans.
Understanding Your Results
- Estimated Payoff Time: How long until every debt reaches $0 with this method.
- Interest Saved: Difference in total interest compared with paying only each minimum (no rollover, no extra).
- Method comparison: Snowball and avalanche results side by side with the same payments, showing numerical differences only.