YourFinanceCoach

Debt snowball vs avalanche

By YourFinanceCoach EditorialUpdated 2 min read

Short answer

The avalanche — highest APR first — always costs less in interest. The snowball — smallest balance first — clears individual debts sooner, which some people find easier to sustain. Run both on your actual figures: if the gap is small, take the one you will finish.

This answers: Should I use the debt snowball or the debt avalanche?

Key takeaways

  • Avalanche always costs less in interest. That is arithmetic, not preference.
  • Snowball clears the first debt sooner, which is a genuine behavioural advantage for some people.
  • The rolling payment does most of the work in both — the ordering rule is the smaller effect.
  • If the gap is under a couple of hundred pounds, pick the one you will complete.

How we chose these

Both methods are simulated month by month on identical inputs: every debt receives its minimum payment, and the whole remaining budget goes to a single target debt — chosen by APR under the avalanche and by balance under the snowball. A cleared debt's payment rolls into the budget for the next. Minimum payments are held at the amount entered rather than falling with the balance, and no new spending is added. The comparison reported is total interest and months to clear under each.

The two methods

Both work the same way: pay the minimum on everything, then put every spare pound into exactly one debt. They differ only in which one.

Avalanche targets the highest APR first, whatever the balance. When it clears, its payment rolls to the next-highest rate.

Snowball targets the smallest balance first, whatever the rate. When it clears, its payment rolls to the next-smallest.

Everything else is identical.

Why avalanche always wins on cost

Every pound sent to a 29.9% debt saves nearly 30p a year. The same pound sent to a 6.9% debt saves 7p. Directing money to the highest available rate at every moment is optimal by construction — no other arrangement of the same payments beats it.

How much it wins by depends on how far apart your rates are. A store card at 29.9% alongside a personal loan at 6.9% produces a large gap. Three cards all around 22% produce almost none, in which case the two methods are near-equivalent and you may as well take the smallest balance for the momentum.

Why snowball sometimes wins in practice

Repayment plans fail when people stop, not when the arithmetic is wrong.

Closing an account entirely — one fewer statement, one fewer minimum, visible progress — feels different from watching a large balance fall slowly. There is evidence that people persist longer when they see accounts eliminated. If clearing a debt in month four keeps you going and grinding through month eighteen does not, the snowball's extra interest may be the cheaper option overall.

The honest test: run both, look at the difference in pounds, and ask whether that amount is worth the extra motivation. £150 over three years probably is. £3,000 is a different conversation.

Put your figures into the debt payoff calculator — it runs both on the same inputs and shows the interest and months for each.

What matters more than the choice

How much you put in. Raising the monthly total shortens the payoff more than reordering it does.

The rolling payment. Holding your total payment constant as debts clear — rather than letting spending absorb the freed-up minimum — is what accelerates the end. Both methods share this, and it is the actual engine.

Not adding new debt. A repayment plan running alongside continued card spending is not a repayment plan.

If neither is affordable

If your combined minimums exceed what you can pay, ordering is not the problem. Contact your lenders before missing a payment — FCA rules require firms to treat customers in financial difficulty fairly.

Then get free advice from MoneyHelper, Citizens Advice, StepChange or National Debtline. All are free. A debt management plan, an IVA, a Debt Relief Order or bankruptcy may each be appropriate depending on your circumstances, and an adviser will tell you which — without charging you and without asking you to stop paying creditors as an opening move.

Run the numbers

Sources

  1. Dealing with debtMoneyHelper
  2. Help with debtCitizens Advice

Educational information only. This page explains how something works in the United Kingdom. It is not financial advice and does not take account of your circumstances. Rates, fees and eligibility change without notice — check the provider’s own terms before you act.

For free, impartial guidance, see MoneyHelper. To complain about a firm, contact the Financial Ombudsman Service.

Related guides