Avalanche vs snowball: which debt payoff method saves you more?

If you have more than one debt, you have a decision to make: which one do you pay off first? Two methods dominate the personal finance conversation. This article explains both, shows you the maths on each, and explains when one is actually better than the other.

The two methods

Debt avalanche (highest interest rate first)

You make minimum payments on every debt, then put all your extra money toward the debt with the highest interest rate. Once that is paid off, you redirect everything to the next highest-rate debt, and so on.

Mathematically, this is optimal. Paying off high-interest debt first eliminates the most expensive borrowing as quickly as possible, which means more of every future payment goes toward principal rather than interest charges.

Debt snowball (lowest balance first)

You make minimum payments on every debt, then put all your extra money toward the debt with the smallest balance. When that debt is eliminated, you take the full payment you were making and redirect it to the next smallest balance.

This method costs more in interest over time, but it produces faster early wins: eliminating a debt entirely, even a small one, provides a psychological reward that helps many people stay on track.

The maths: a concrete example

Suppose you have three debts and $500 per month to put toward them:

• Credit card A: $2,400 balance, 22% APR, $60 minimum
• Credit card B: $5,800 balance, 17% APR, $120 minimum
• Personal loan: $11,000 balance, 9% APR, $220 minimum

After minimums ($400/month), you have $100 extra to allocate.

Avalanche result: Total interest paid: $3,240. Debt-free in 34 months.

Snowball result: Total interest paid: $3,680. Debt-free in 36 months.

In this example, the avalanche saves $440 and gets you debt-free two months earlier. The gap gets larger with higher balances and higher interest rates. For someone with $30,000 in credit card debt, the difference can exceed $3,000 in total interest.

When snowball is the right choice anyway

The snowball method is not irrational. Research on debt repayment behaviour consistently shows that people who eliminate accounts early are more likely to stay committed to their repayment plan. A quick win early in the process reduces the psychological weight of the debt and reduces the chance of abandonment.

If you have tried and failed to pay off debt before, the snowball method may be the right starting point. A plan you actually follow beats a mathematically optimal plan you abandon.

Hybrid approaches

Some people use the snowball to clear 1 or 2 small debts quickly (reducing the number of accounts to manage), then switch to the avalanche for the remaining larger debts. This captures some of the motivational benefit of early wins while still minimising total interest on the larger balances.

What actually matters most

The interest rate difference between avalanche and snowball is usually smaller than the difference between having a plan at all and not having one. Before optimising for the method, make sure:

• You know the exact balance, rate, and minimum payment for every debt
• You have a concrete monthly number to allocate to debt payoff beyond minimums
• You have a written payoff date for each debt so progress is visible

The payoff date is the most motivating number in the whole calculation. Knowing you will be free of a specific debt on a specific month changes your relationship with the payment.

See your own numbers

The calculations above are straightforward to run for your own debts: enter your balances, rates, minimums, and extra payment amount, and the model computes your exact debt-free date under each method.