The Debt Avalanche Method, Explained

If you’re juggling more than one debt, the order you pay them off in changes how much interest you end up handing over, sometimes by hundreds of dollars. The debt avalanche method picks that order using one rule: always send your extra money to the debt with the highest interest rate, no matter how big or small its balance is.

The core idea: rate first, balance second

Every debt you carry is quietly charging you interest every month, and the rate is what determines how fast that debt grows if you ignore it. A $2,000 balance at 24% accrues interest faster, relative to its size, than a $10,000 balance at 8%. The avalanche method leans into that fact directly: you make the minimum payment on everything, then throw every extra dollar you can spare at whichever debt has the highest annual rate, regardless of which one has the largest or smallest balance.

Once that highest-rate debt is paid off, its minimum payment doesn’t disappear. It rolls into the extra payment you’re throwing at the next-highest-rate debt, so your total monthly firepower keeps growing as each debt clears. This is the same “snowballing” mechanism the debt snowball method uses, they just disagree on which debt gets the extra money first. Snowball orders by smallest balance for quick psychological wins; avalanche orders by highest rate to minimize the interest bill. Because avalanche always targets the rate that’s costing you the most, it’s the mathematically optimal order: no other sequence you could choose produces less total interest over the life of all your debts combined. The tradeoff is that if your highest-rate debt also happens to have a large balance, you might go longer without the satisfaction of fully closing out any single account.

The mechanics

The simulation behind the avalanche method runs one month at a time, in this order:

1. Every debt with a balance accrues interest for the month
   (balance x annual rate / 12).
2. Every debt gets its minimum payment.
3. Extra payment + minimum payments freed up from
   already-paid-off debts all go toward the debt with
   the highest interest rate that's still active.
4. Repeat until every balance hits zero.

The key line is step 3. As soon as a debt is paid off, its minimum payment doesn’t vanish, it gets added to the pile of extra money aimed at the next debt in line, ranked by rate. That’s what makes the payoff accelerate over time instead of staying flat.

Worked example

Say you have three debts and $200 a month to put toward extra payments beyond the minimums:

• Debt 1: $5,000 balance at 22% interest, $100 minimum payment
• Debt 2: $3,000 balance at 18% interest, $75 minimum payment
• Debt 3: $8,000 balance at 15% interest, $150 minimum payment

Ranked by rate, the avalanche order is debt 1, then debt 2, then debt 3, even though debt 3 has the largest balance and debt 2 has the smallest. Every month, all three debts get their minimum payment, and the full $200 extra goes to debt 1 until it’s gone. Then debt 1’s freed-up $100 minimum joins the $200 and both get redirected to debt 2, and so on down the line.

Run that simulation to completion and you’re debt-free in 42 months, having paid $5,101.75 in total interest.

Now compare that to the debt snowball method on the exact same three debts, same balances, same rates, same minimums, same $200 extra a month, just ordered smallest balance first (debt 2, then debt 1, then debt 3) instead of highest rate first. Snowball clears the same debts in the same 42 months, but costs $5,336.77 in total interest, $235.02 more than avalanche. Both methods get you to zero on the same schedule here; avalanche just gets you there for less, because it kept the 22% and 18% balances from accruing interest for as long as snowball’s order allowed them to.

When it doesn’t matter: tied interest rates

If two of your debts have the exact same interest rate, the avalanche method doesn’t care which one you tackle first between them, the total interest paid comes out identical either way. In that situation, a lot of people default to paying off the smaller balance first anyway, purely for the motivational lift of closing an account sooner. That’s a reasonable tiebreaker and doesn’t cost you anything mathematically, since the tie means neither order is actually better.

FAQ

Is the debt avalanche method always cheaper than the debt snowball method? Yes. Targeting the highest interest rate first always results in equal or lower total interest paid compared to any other payoff order, including snowball’s smallest-balance-first approach. How much you save depends on how spread out your rates are: a wide gap between your highest and lowest rate means avalanche saves you more, while similar rates across debts mean the two methods land close together.

Why would anyone choose snowball if avalanche saves more money? Motivation. Snowball is built around paying off your smallest balance first, so you get a full account closed out sooner, which some people find keeps them more consistent with the plan over months or years. Avalanche is the better math; snowball can be the better habit for some people. Neither is wrong, they’re optimizing for different things.

Does it matter if my highest-rate debt also has the biggest balance? Not for the math, avalanche still targets it first regardless. It does mean you may go longer before any single debt is fully paid off, since a big, high-rate balance takes time to clear even with extra payments directed at it. If that delay is a problem for you personally, that’s the main practical argument for switching to snowball instead.

Use the Debt Avalanche Calculator to run your own numbers.