Debt Snowball vs Avalanche: Which Should You Pick?

Both methods work the same way: pay the minimum on every debt, then put all your spare money on one target. The debt snowball targets the smallest balance first. The debt avalanche targets the highest interest rate first. Avalanche usually costs less interest, and snowball clears whole accounts sooner. On the three debts below the gap is £458.25 of interest.

This article runs both methods on the same debts, shows the numbers side by side and says when each one makes sense.

What is the difference between debt snowball and avalanche?

Both are defined in the glossary: debt snowball and debt avalanche. The APR is the yearly interest rate, and the calculators divide it by 12 to add interest each month.

A worked example: the same three debts under both methods

Take £9,500 of debt spread over three accounts, with £600 a month available to pay them. The minimums add up to £310, so £290 a month is spare.

This is a deliberately awkward set. The credit card has the highest rate, but the store card has the smallest balance, so the two methods pick different targets.

Snowball puts the £290 on the store card first (smallest balance), then the personal loan, then the credit card. Avalanche starts with the credit card (27.9%), then the store card (19.9%), then the personal loan (8.9%).

Here is how each plan plays out, with every payment counted from the first month:

Avalanche finishes a month earlier and costs £458.25 less. The reason is on the credit card: £5,000 at 27.9% adds £116.25 of interest in the first month alone, and snowball pays only its minimum until the personal loan clears in month 11.

Snowball is not just worse, though. It removes two accounts inside a year, which means two fewer minimums to track and two fewer statements to open. Avalanche gives you nothing to tick off for 14 months.

Try your own debts

The calculator below is the debt snowball tool, and it also shows the avalanche result for the same debts, so you can compare them directly. It opens with a different example: a £3,000 credit card at 29.9%, a £1,200 store card at 34.9% and a £5,000 personal loan at 9.9%, with £650 a month. In that case the smallest debt is also the most expensive one, so both methods give the same answer and the comparison shows no difference.

To reproduce the table above, replace the three debts and the budget with the figures from the worked example. Then look at the comparison panel for the interest and timing gap.

Prefer to see the avalanche plan on its own, with the interest saved against paying minimums only? Use the debt avalanche calculator.

When does the snowball method make sense?

The snowball method is a good fit when:

• Your rates are close together. If every debt sits within a few points of the others, ordering by APR saves little, and ordering by balance costs little.
• You are close to giving up. A plan you abandon in month 8 saves nothing. Clearing an account early is a visible win, and some people need one. That is a personal judgement rather than a rule, and this article makes no claim about how many people it helps.
• You want fewer accounts. Each cleared account is one less payment date, one less login and one less thing to forget.

When does the avalanche method make sense?

Avalanche is the better pick when:

• One debt is much more expensive than the rest. A 28% card next to a 9% loan is the clearest case. The bigger the spread in rates, the more avalanche saves.
• The expensive debt is also large. A big balance at a high rate is where interest accumulates fastest.
• You will follow a plan you can see on a spreadsheet. If the numbers motivate you, the lower total cost is its own reward.

What do both methods leave out?

Both calculators are planning tools, not statements. They add interest monthly at APR ÷ 12, and they do not model fees, daily interest, a lender’s own minimum-payment rules or a 0% balance-transfer offer. Your lender’s figures are the ones that count.

Three things matter more than the method:

1. Cover priority debts first. Rent, mortgage, council tax, energy bills and court fines come before any card or loan. If you are behind on those, get free, independent debt advice before choosing a payoff order.
2. Pay every minimum. Neither plan works if a minimum is missed.
3. Keep a small buffer. A small emergency fund stops one unexpected bill going straight back onto a card.

What to do next

List every debt with its balance, APR and minimum, and add up what you can pay each month. Put them into the debt snowball calculator above to see both plans, or the debt avalanche calculator for the avalanche plan alone.

If one debt is a single credit card, the credit card payoff calculator shows how overpaying changes the time and cost. For a loan on its own, the loan repayment calculator gives the monthly payment and total interest. The same idea of interest charged on what you still owe is covered in how a mortgage repayment is calculated.

• debt
• debt snowball
• debt avalanche
• interest