Debt Snowball vs Avalanche: Which Method Clears Debt Faster?

How it works: list all your debts from highest interest rate to lowest. Make minimum payments on everything, then put all your extra money towards the highest-interest debt. Once that's cleared, move to the next highest, and so on. Example: you have a credit card at 22% APR (£1,500), a personal loan at 8% (£3,000), and an overdraft at 15% (£800). The avalanche method says tackle the credit card first (22%), then the overdraft (15%), then the personal loan (8%). This saves you the most money in total interest because you're eliminating your most expensive debt first.

How it works: list all your debts from smallest balance to largest, regardless of interest rate. Make minimum payments on everything, then put all your extra money towards the smallest balance. Once that's cleared, roll that payment into the next smallest, and so on. Using the same example: tackle the overdraft first (£800), then the credit card (£1,500), then the personal loan (£3,000). The snowball method costs slightly more in total interest, but you get quick wins — clearing the overdraft gives you momentum and proof that you're making progress.

Mathematically, the avalanche method always costs less in total interest. If you have £500/month to put towards debt repayment across the debts in our example, the avalanche method would clear all debt about 1-2 months faster and save £200-£400 in interest compared to the snowball method. The bigger the difference in interest rates between your debts, the more the avalanche saves. If all your debts have similar interest rates, the difference between the two methods is minimal, and it barely matters which you choose.

Research by Harvard Business School found that people using the snowball method were more likely to actually become debt-free. Why? Because paying off a whole debt — even a small one — gives you a psychological boost that keeps you going. The avalanche method can feel demoralising if your highest-interest debt is also your largest balance. Months of payments with no debt fully cleared can sap motivation. The snowball method's quick wins create momentum. Each cleared debt simplifies your finances and reinforces that your effort is working. For many people, that motivation is worth the extra cost.

Use the avalanche if: you're disciplined and motivated by maths and efficiency, your highest-interest debt isn't also your largest balance, or the interest rate differences are significant (paying 22% on one debt and 5% on another makes the avalanche clearly better). Use the snowball if: you need quick wins to stay motivated, you've tried and failed to repay debt before, your debts are similar in interest rate, or you have several small debts that could be cleared quickly. A hybrid approach also works: if your smallest debt and highest-interest debt are the same (or close), you get the benefits of both methods.

Regardless of which method you choose, some principles apply to both: stop adding new debt (cut up cards if necessary), automate minimum payments on all debts so you never miss one, throw every extra pound at your target debt (windfalls, overtime, selling stuff), track your progress visually (a chart on the fridge, an app, a spreadsheet — seeing the numbers drop is motivating), and celebrate clearing each debt (modestly — don't reward yourself by spending). The method matters less than the commitment. Both strategies work if you stick with them.