Debt Avalanche vs Debt Snowball: Which Saves You More?
If you've got more than one debt, you've got a decision to make.
Not whether to pay them off — obviously yes. But which one to focus on first. Because throwing extra money at your debts in the wrong order costs you more than it should.
There are two methods that give you a clear answer to this. Both work. They just optimise for different things.
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The Two Methods
Debt Avalanche
List all your debts. Order them by interest rate, highest to lowest. Pay the minimums on everything, then throw every spare pound at the debt with the highest rate.
When that's gone, move to the next highest rate. Repeat.
You're attacking the most expensive debt first — the one costing you the most in interest every single month. Mathematically, this is the fastest route out of debt and the one that costs you the least overall.
Debt Snowball
List all your debts. Order them by balance, smallest to largest. Pay the minimums on everything, then throw every spare pound at the smallest balance.
When that's gone — and it goes quickly — you roll that freed-up payment into the next smallest debt. The payments stack up as you go, like a snowball rolling downhill.
You're not minimising interest. You're maximising early wins. The logic is psychological: clearing a debt completely, even a small one, gives you momentum that keeps you going.
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A Real Example
Say you have two debts:
- Credit card — £3,000 balance at 24% APR, minimum payment £60/month
- Overdraft — £800 balance at 15% APR, minimum payment £25/month
You have £200/month total to put towards debt, so £115 spare after minimums.
Snowball says: attack the overdraft first (smaller balance). Put your £115 extra there.
Avalanche says: attack the credit card first (higher rate). Put your £115 extra there.
Here's what happens:
| | Snowball | Avalanche |
|---|---|---|
| Order of payoff | Overdraft first, then credit card | Credit card first, then overdraft |
| Total interest paid | ~£995 | ~£888 |
| Time to debt-free | ~24 months | ~24 months |
Avalanche saves roughly £107 in interest, even though both methods take about the same time to clear the debt in this example.
That's a modest difference here. On larger debts with bigger rate gaps, the difference is much more significant.
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When Avalanche Wins
Avalanche is the better choice when:
- You have high-rate debt — credit cards, store cards, buy-now-pay-later — sitting alongside lower-rate debt
- The interest rate gap between your debts is large
- You're disciplined and motivated by knowing you're doing it the optimal way
- The maths matters more to you than the psychology
The higher the rates on your worst debt, the more avalanche saves you. A credit card at 39% APR is bleeding you every month — getting rid of that first makes a material difference.
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When Snowball Wins
Snowball is the better choice when:
- You've tried to pay off debt before and lost motivation partway through
- You have several small debts that feel overwhelming
- You want to see something completely gone quickly
- The psychological boost of clearing a debt outweighs the interest saving
The honest truth is that the best debt payoff method is the one you actually stick to. Avalanche is theoretically superior. But if avalanche makes you feel like you're making no progress for 18 months and you give up — snowball would have been better.
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They're Sometimes the Same Thing
Worth noting: the two methods only diverge when your highest-rate debt isn't also your smallest.
If your most expensive debt is also your smallest — a store card, an overdraft, a small personal loan — both methods point at the same target. In that case, just start there.
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A Hybrid Approach
Some people combine the two. Clear one or two small debts first to get momentum and reduce the number of payments to juggle, then switch to avalanche for the rest.
There's no rule against this. The goal is to pay off your debt, not to follow a method perfectly.
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What to Do Right Now
- List every debt you have — balance, interest rate, and minimum payment
- Add up your minimum payments — this is your floor
- Work out how much extra you can put toward debt each month — even £30 or £50 makes a difference
- Pick a method — avalanche if you want to minimise cost, snowball if you need early wins
- Start. Don't adjust for the first three months.
The biggest mistake isn't choosing the wrong method. It's not choosing at all and continuing to pay minimums on everything indefinitely.
If you need help finding room in your budget for extra debt payments, start with our guide to [building a zero-sum budget in the UK](/blog/how-to-build-a-zero-sum-budget-uk). If your monthly outgoings still feel fuzzy, [tracking household bills properly](/blog/how-to-track-household-bills-uk) usually shows where the spare cash is hiding.
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Work Out Your Own Numbers
Every debt situation is different. The right answer depends on your rates, your balances, and how much you can put in each month.
Groat's [Debt Payoff Calculator](/calculators/debt) lets you enter your actual debts and compare avalanche against snowball side by side, so you can see exactly how much each method costs you and how long it takes.
If you want to turn that result into a full monthly plan, use the calculator first, then pair it with a [zero-sum budget](/blog/how-to-build-a-zero-sum-budget-uk) so the overpayment actually happens.
It's free to use, with no account required.
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Summary
Both methods work. Neither is wrong.
Avalanche — highest rate first. Saves the most money. Best if you're motivated by doing it optimally.
Snowball — smallest balance first. Clears debts faster. Best if you need psychological wins to stay on track.
If your highest-rate debt is also your smallest, they're the same thing. Start there.
The only bad move is paying minimums on everything and hoping it sorts itself out.
— Team Groat