Personal Finance
Pay Off Debt Faster: Avalanche vs Snowball
When you have multiple debts - a credit card here, an overdraft there, a personal loan from last year - the question is: which one do you kill first? Two methods dominate the personal finance world, and they disagree on the answer.
The two methods
Debt Avalanche
Pay minimums on everything. Throw every extra pound at the debt with the highest interest rate. When that is gone, roll its payment into the next-highest-rate debt. Repeat.
Mathematically optimal. Minimises total interest paid.
Debt Snowball
Pay minimums on everything. Throw every extra pound at the smallest balance, regardless of interest rate. Kill it, then roll onto the next smallest. Repeat.
Psychologically optimal. Builds visible, fast wins.
Which one saves more money?
Avalanche. Always. It is a mathematical fact - by attacking the highest interest rate first, less interest accrues while you work through your balances. On a typical mix of debts (22% credit card, 39% overdraft, 7% personal loan), avalanche can save £500-£2,000 compared to snowball across a 2-3 year payoff.
Example: £10,000 of debt, £400/month extra
- £500 store card @ 29.9%
- £2,000 overdraft @ 39.9%
- £3,500 credit card @ 22.9%
- £4,000 personal loan @ 7.9%
Avalanche: Kill overdraft first, then store card, then credit card, then loan. Total interest: ~£1,850.
Snowball: Kill store card first, then overdraft, then credit card, then loan. Total interest: ~£2,150.
Avalanche wins by £300 and finishes a month sooner.
So why does anyone choose snowball?
Because personal finance is 20% maths and 80% behaviour. Snowball gives you a debt fully paid off in weeks, not months. That first win changes how you feel - it proves the system works, it proves you can do it. For people who have tried and given up before, that psychological boost is worth the couple hundred extra pounds in interest.
The worst method is the one you abandon. If you know yourself and you need momentum, snowball. If you are spreadsheet-motivated and trust the numbers, avalanche.
A hybrid approach
Many people do well with a modified strategy:
- Knock out any tiny debts first (under £500) for the quick win
- Then switch to pure avalanche - attack the highest rate until debt-free
- Use 0% balance transfer cards aggressively to cut the interest rate itself
How to use our calculator
Our Debt Payoff Calculatorlets you put in every debt, pick your method, and see both a month-by-month schedule and the total interest you will pay. Change the extra payment and watch how every additional £50/month can chop months - sometimes years - off your payoff date.
Walkthrough:
- List every debt with balance, APR, and minimum payment
- Enter the total extra you can afford each month above minimums
- Toggle between avalanche and snowball to see both timelines
- Stress-test: what happens if you find an extra £100/month? £200?
The real lesson
Avalanche vs snowball matters less than the extra payment itself. Whether you pay the right debt first or the wrong debt first, you will get out - as long as you keep throwing money at it. Pick the method you can stick to for two years straight and start tonight.