Debt Avalanche Calculator: Pay Off High-Interest Debt First
The debt avalanche is the mathematically optimal strategy for paying off multiple debts. The rule is simple: after making minimum payments on every debt, direct every extra dollar toward the debt carrying the highest interest rate. Once that debt is gone, roll its payment onto the next highest-rate debt. This focuses your money where interest is most damaging, saving the maximum amount over the life of your debts. This calculator simulates the avalanche strategy across up to five debts. Enter each debt's name, balance, annual interest rate, and minimum payment, then enter any extra monthly amount you can put toward debt above the minimums. The calculator runs the simulation month by month, tracks when each debt is paid off, and totals the interest paid. It also runs a minimum-payment-only baseline so you can see exactly how much interest the avalanche strategy saves. The payoff order is listed so you know which debt gets the focus first. If two debts have the same rate, the one with the smaller balance is paid off first to free up cash sooner.
Formulas
Step 1: Sort active debts by APR descending. Ties broken by balance ascending (smaller balance first).
Step 2 (each month):
For each debt: add monthly interest = balance x (APR / 12 / 100)
Pay each debt's minimum payment
Apply all extra payment to the highest-APR debt with remaining balance
When a debt reaches zero, add its minimum to the extra pool (debt rollover)
Step 3: Track when each debt reaches zero (payoff order) and total interest paid
Minimum-only baseline: same simulation with extra = 0, no debt rollover
Interest saved = minimum-only total interest - avalanche total interest
How to use this calculator
- Enter a name, current balance, annual interest rate, and minimum monthly payment for each debt. Leave unused rows with a balance of zero.
- Enter the extra monthly amount you can commit above the total minimums. Even a small amount accelerates payoff significantly.
- Read the payoff order to know which debt to focus on first (the one with the highest APR).
- Note the total months to debt-free and total interest paid under the avalanche strategy.
- Compare with the minimum-only interest figure to see your interest savings from the avalanche approach.
- As each debt is paid off, continue directing its former payment plus your extra toward the next debt in the payoff order.
Frequently asked questions
What is the debt avalanche method?
The debt avalanche (also called highest-rate-first or mathematically optimal method) directs any money above the minimum payments to the debt with the highest interest rate. Once that debt is paid off, the freed-up payment is rolled onto the next highest-rate debt, and so on. This minimizes the total interest paid over the life of all debts.
How does the avalanche compare to the snowball method?
The avalanche minimizes total interest paid, making it mathematically optimal. The snowball (smallest balance first) costs more in interest but provides quicker early wins by eliminating accounts faster. Research suggests the psychological benefit of early wins can help some people stay on track. If you need motivation to stick with a plan, the snowball may be more effective in practice even if it costs more on paper.
What counts as an extra payment?
Any amount above the required minimum payments across all your debts. Even $50 extra per month can meaningfully accelerate payoff and reduce total interest. The avalanche concentrates all extra dollars on the highest-rate balance to maximize interest savings.
Should I include my mortgage in the avalanche?
Generally, mortgage rates are lower than consumer debt rates, so most people pay minimums on their mortgage and target higher-rate debts first. Whether to accelerate mortgage payoff after all other debt is cleared is a separate decision that depends on your rate, tax situation, and investment returns available.
What happens when a debt is fully paid off?
In the avalanche method, the monthly payment that was going to the paid-off debt (minimum plus any extra assigned to it) is redirected to the debt now at the top of the queue. This is called the debt rollover or snowball effect. It accelerates the payoff of remaining debts.
Official sources
- CFPB: Strategies for paying off debt: consumerfinance.gov.
- Federal Trade Commission: Coping with Debt: consumer.ftc.gov.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.