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Free Debt Payoff Calculator (avalanche vs snowball)

See your debt-free date and total interest paid for both repayment methods.

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What this calculator does

Enter your debts, minimum payments, and any extra you can put toward debt each month. The calculator simulates two strategies: avalanche (pay highest interest rate first, mathematically optimal) and snowball (pay smallest balance first, behaviourally easier). Output: debt-free date and total interest under each.

How it works

  1. 1

    Add each debt

    Name, balance, interest rate (APR), minimum monthly payment.

  2. 2

    Set extra payment

    Any amount you can put toward debt above the minimums. Even $100/month moves the needle.

  3. 3

    Pick a method

    Avalanche saves the most interest. Snowball gives faster psychological wins. The chart shows both.

  4. 4

    See your debt-free date

    Month-by-month simulation across all debts.

  5. 5

    Adjust to optimise

    Try different extra-payment amounts to see how each accelerates your debt-free date.

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Common questions

Avalanche or snowball — which is better?▾
Avalanche is mathematically optimal — paying the highest-APR debt first minimises total interest. Snowball pays the smallest balance first, giving early wins that some people need to stay motivated. The interest difference is usually 5-15%. Pick the one you will actually stick with.
Should I stop investing to pay off debt?▾
Standard advice: any debt with APR > 7-8% should be paid off before investing beyond an employer 401k match. Below 7%, the math typically favours investing.
What about consolidation?▾
Consolidating high-APR credit cards into a lower-rate personal loan or 0% balance transfer card can save thousands. The calculator does not model this directly — but you can update the rate on a debt entry to see the effect.
Does paying minimums extend my timeline?▾
Massively. Credit card minimums are typically 1-2% of balance. At 20% APR, a $5,000 balance paid at minimums takes ~30 years and costs ~$11,000 in interest. Any extra payment dramatically compresses this.

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