The two methods in one line
This is education, not personal advice. Both methods do the same two things — pay the minimum on every debt, and throw all spare money at one chosen target until it's gone, then roll that freed-up payment onto the next. They differ only in which debt is the target:
- Avalanche — target the highest interest rate first. Clears debt for the least total interest, fastest. Mathematically optimal.
- Snowball — target the smallest balance first. Costs a little more interest, but you fully clear a debt sooner, which is motivating.
A worked comparison
Say you have three non-priority debts and £200/month spare after minimums:
| Debt | Balance | APR |
|---|---|---|
| Store card | £400 | 29% |
| Credit card | £2,500 | 23% |
| Personal loan | £1,200 | 9% |
Avalanche order: store card (29%) → credit card (23%) → loan (9%). Lowest total interest, quickest payoff. Snowball order: store card (£400) → loan (£1,200) → credit card (£2,500). Here the store card happens to be both smallest and highest-rate, so the two methods agree on step one — common in practice. They diverge at step two: avalanche keeps attacking the 23% card; snowball clears the smaller £1,200 loan first for a faster "one down" feeling, paying a bit more interest overall.
Maths vs motivation
Avalanche always wins on a spreadsheet — less interest, less time. But debt payoff is behavioural as much as financial: research and lived experience both show that the early, visible win of fully clearing a debt (snowball) helps many people keep going, and the method you actually finish beats the optimal one you abandon. Decide honestly which risk is bigger for you: paying some extra interest, or losing momentum and stopping.
Which to choose
- Pick avalanche if the interest-rate gap between debts is large (so the saving is meaningful) and you're motivated by the numbers.
- Pick snowball if you've struggled to stick with payoff before and need an early, tangible win to stay on track.
- Hybrid is fine: clear one tiny balance first for the morale boost, then switch to strict avalanche.
UK priority debts come first (important)
Neither method applies to priority debts. In the UK, arrears on rent, mortgage, council tax, energy and gas, court fines, and tax carry severe consequences — eviction, bailiffs, disconnection, prison in extreme cases — regardless of interest rate. These must be brought up to date first. Snowball/avalanche are only for non-priority debt (credit/store cards, personal loans, overdrafts, catalogue/BNPL) once priorities are safe.
If debts are unaffordable, free, impartial UK help is available — MoneyHelper, StepChange and National Debtline — and using it early is a strength, not a failure.
FAQs
What is the difference between the debt snowball and avalanche?
Both pay minimums on everything and throw all spare money at one target. Avalanche targets the highest interest rate first (least total interest, fastest). Snowball targets the smallest balance first (slightly more interest, but an early "debt gone" win that's easier to sustain).
Which is better, snowball or avalanche?
Avalanche on pure maths — it minimises interest and time. Snowball is often better in practice for people who need visible early progress, because the method you stick to beats the optimal one you abandon. Big rate gap → lean avalanche; motivation is the real risk → snowball is defensible.
Do these methods apply to UK priority debts?
No. Rent, mortgage, council tax, energy and court-fine arrears have serious consequences regardless of interest rate, so they're dealt with first. Snowball/avalanche are only for non-priority debt once priorities are safe.
Should I save while paying off debt?
Keep a small starter emergency buffer so a surprise doesn't push you back onto the card, then attack expensive debt hard — clearing a 20%+ APR debt is a guaranteed, tax-free return almost nothing else beats.
Related guides and calculators
Debt basics guide — the foundations. Everyday money — priority vs non-priority and the wider plan. Balance transfer planner — cut the interest while you clear it. Emergency fund guide — the buffer that stops the cycle. Should I save or invest — once the debt's gone. Money basics: start here — the full ordered routes.
How UK Tax Drag holds itself to account
Every page is reviewed against the editorial standards, written from primary sources, sourced openly, and corrected publicly. No affiliate revenue. No sponsored content. No paid placements.