Guide · 4 minute read

Avalanche vs snowball: which debt do I pay off first?

Pay the debt with the highest interest rate first (the avalanche) if you want to pay the least overall. Pay the smallest balance first (the snowball) if you need quick wins to stay motivated, and accept it usually costs a bit more.

Minimum payments come first, whatever you choose

Both methods start the same way: pay the contractual minimum on every single debt, every month, no exceptions. Missed minimums mean late fees, penalty interest and credit file damage that outweighs anything either strategy saves.

The strategy only decides where the spare money goes. If your minimums total £150 a month and you can put £400 at your debts, the question is which debt gets the extra £250. When a debt clears, its minimum payment joins the spare pool automatically, so the attack on the next debt gets stronger over time. That accelerating effect is where both names come from.

Avalanche: highest rate first, lowest cost

The avalanche sends every spare pound at the debt with the highest APR, regardless of its size. Once that clears, you move to the next highest rate, and so on.

The logic is plain: a pound of debt at 25% costs you 25p a year, a pound at 8% costs 8p. Killing the expensive pounds first means less interest accrues each month, so more of every payment hits the actual balance. Mathematically, avalanche never loses. The only question is by how much it wins, and that depends on how far apart your rates are and how big the expensive balance is.

Snowball: smallest balance first, fastest wins

The snowball sends the spare money at the smallest balance instead. A £600 store card might be gone in two or three months, and crossing a debt off the list entirely feels very different from watching a big number shrink slowly.

That feeling is the whole argument. Research on debt repayment behaviour consistently finds that people who see early progress are more likely to keep going. A plan that costs £200 more in interest but actually gets finished beats a mathematically perfect plan abandoned in month four.

A worked example with real numbers

Say you owe £4,000 on a credit card at 25% APR (minimum £100 a month) and £1,500 on a personal loan at 8% (minimum £50), and you can put £400 a month at the pair. Run it through the debt payoff planner and here is what happens:

• Avalanche (card first): debt-free in 16 months, total interest £737.
• Snowball (loan first): debt-free in 17 months, total interest £960, but the loan is cleared by month 6.

Avalanche saves £223 and a month. Snowball buys you a fully paid-off debt within half a year. Neither answer is wrong; they are paying for different things.

One more wrinkle: the two methods often agree. If your smallest debt also carries your highest rate, a £1,200 store card at 30% sitting next to a £3,000 credit card at 24%, say, both strategies attack the store card first and the difference is exactly zero. Check before you agonise.

So which should you pick?

Pick avalanche if the numbers motivate you, your rates differ widely (a 28% card next to a 6% loan), or your most expensive debt is also large, because that is where the savings get serious. Pick snowball if you have several small debts cluttering the picture, you have started and quit debt plans before, or you know yourself well enough to admit you need the early win.

A reasonable hybrid: clear one small debt first for momentum, then switch to avalanche for the rest. And whichever you choose, the size of the monthly number matters far more than the order. Finding an extra £50 a month with the budget planner beats any amount of strategy optimisation. Run your own debts through the debt payoff planner and look at the "interest saved" figure: if it is small, take the snowball guilt-free.

Common questions

Should I use a 0% balance transfer instead?

Often, yes, before either strategy. Moving expensive card debt to a 0% balance transfer card stops the interest while you repay. Watch the transfer fee (typically 3 to 4%) and make sure you can clear the balance before the 0% window ends, or the rate jumps back up.

Should I pay off debt or build savings first?

Set aside a small starter buffer of around £1,000 first, so a surprise bill does not go straight back on the card, then put everything spare at the expensive debt. Cards at 20%+ charge far more than savings earn. See our emergency fund guide for the full sequencing.

What if I cannot even cover the minimum payments?

Neither method applies yet. Speak to a free, non-profit debt charity: StepChange, National Debtline or Citizens Advice. They negotiate with lenders and set up affordable plans, and they do everything paid debt-management firms do without the fees.

Does overpaying debt hurt my credit score?

No, reducing balances lowers your credit utilisation, which generally helps your score. Closing old accounts after clearing them can trim your average account age, but the effect is small next to the benefit of carrying less debt.

Should I include my mortgage or student loan in the plan?

Usually not. UK student loans work more like a tax than a debt, and mortgage rates are typically far below card rates, so both sit outside the avalanche queue. Focus the method on cards, overdrafts, store cards and personal loans.

Guidance and education, not regulated financial advice.