Wealth & FIRE

Avalanche vs Snowball: We Calculated Which Debt Payoff Method Wins

We ran the numbers on both debt payoff strategies. The maths is clear, but the best method might surprise you.

LifeByNumbersPublished on December 5, 20258 min min read

You've got multiple debts. Credit cards, car loan, perhaps student loans. You want out. But which payoff strategy actually works best?

We ran both methods through our Debt Payoff Calculator with real numbers. The results reveal something interesting: the "best" method depends on more than just maths.

The Two Methods Explained

The Avalanche Method (Maths-Optimal)

Pay minimum on everything, then throw extra money at the highest interest rate debt first.

How it works:

  1. List debts by interest rate (highest to lowest)
  2. Pay minimums on all debts
  3. Put every extra pound toward the highest-rate debt
  4. When that's paid off, roll that payment to the next highest rate

The Snowball Method (Psychology-Optimal)

Pay minimum on everything, then throw extra money at the smallest balance first.

How it works:

  1. List debts by balance (smallest to largest)
  2. Pay minimums on all debts
  3. Put every extra pound toward the smallest balance
  4. When that's paid off, roll that payment to the next smallest

We Ran the Numbers: A Real Scenario

Using our Debt Payoff Calculator, here's what happens with a typical UK debt profile:

The Debts:

DebtBalanceInterest RateMinimum Payment
Credit Card A£6,50022.9%£150
Credit Card B£2,40018.9%£60
Car Finance£9,0007.9%£275
Personal Loan£15,0006.4%£220

Total Debt: £32,900 Extra Monthly Payment: £400

Avalanche Results (Highest Rate First):

  • Order of payoff: Credit Card A → Credit Card B → Car Finance → Personal Loan
  • Total time to debt-free: 38 months
  • Total interest paid: £5,847
  • First debt eliminated: Month 11 (Credit Card A)

Snowball Results (Smallest Balance First):

  • Order of payoff: Credit Card B → Credit Card A → Car Finance → Personal Loan
  • Total time to debt-free: 40 months
  • Total interest paid: £6,423
  • First debt eliminated: Month 4 (Credit Card B)

The Verdict:

MetricAvalancheSnowballWinner
Time to debt-free38 months40 monthsAvalanche
Interest paid£5,847£6,423Avalanche
First winMonth 11Month 4Snowball
Interest saved--£576 saved with Avalanche

Run your own comparison →

Why Avalanche Doesn't Always Win

The maths is clear: Avalanche saves money. So why does anyone use Snowball?

The Psychology Factor

Research from behavioural economists found that people who paid off accounts faster (Snowball) were more likely to eliminate all their debt. The early wins created motivation.

The uncomfortable truth: The best debt payoff strategy is the one you actually stick with.

***** If you've tried Avalanche and given up, Snowball might save you more money in practice—even if it costs more in theory.

When Snowball Beats Avalanche

  1. You need motivation - If you've failed at debt payoff before
  2. Similar interest rates - If rates are within 2-3% of each other
  3. Many small debts - Quick wins reduce accounts to manage
  4. High stress levels - Fewer debts = less mental load

When Avalanche Is the Clear Winner

  1. One debt has a much higher rate - 22%+ credit card vs 7% car finance
  2. You're highly disciplined - Numbers motivate you more than wins
  3. Large high-interest debt - Waiting costs serious money
  4. You've done this before - You know you'll stick with it

The Hybrid Approach: Best of Both

Here's a strategy financial advisers often recommend:

Step 1: Knock out one small win first

Pay off your smallest debt for an instant motivation boost.

Step 2: Switch to Avalanche

Attack the highest interest rate debt with everything you've got.

Step 3: Stay the course

Use automation to remove willpower from the equation.

Using our example:

  1. Pay off Credit Card B first (£2,400) - Done in 4 months
  2. Then attack Credit Card A (£6,500) - The 22.9% killer
  3. Roll everything to car finance, then personal loan

Result: Quick win psychology + optimal maths after month 4.

Real Scenarios: Which Method Should You Use?

Scenario A: High-Rate Credit Card Debt

Your situation:

  • £12,000 on a 24.9% APR credit card
  • £6,000 on an 18.9% APR card
  • £4,000 car finance at 5.9%

Recommendation: Avalanche

The 24.9% card is costing you £2,988/year in interest. Every extra pound toward that card is earning you 24.9% guaranteed.

Scenario B: Many Small Debts

Your situation:

  • £800 catalogue debt (28% if not cleared)
  • £2,000 credit card at 19.9%
  • £2,500 overdraft at 39.9% EAR
  • £3,500 credit card at 18.9%

Recommendation: Address the overdraft first, then Hybrid

That 39.9% overdraft is toxic. Clear it immediately, then use Snowball for the mental relief of fewer accounts.

Scenario C: Plan 2 Student Loan + Consumer Debt

Your situation:

  • £45,000 in Plan 2 student loans at RPI + 3%
  • £8,000 credit card at 21.9%

Recommendation: Avalanche (focus on the credit card)

Student loans in the UK are more like a graduate tax than true debt. They're wiped after 30 years and only repaid at 9% above £27,295. That credit card is the real emergency—attack it first.

! Unlike consumer debt, UK student loans don't affect your credit score and have income-based repayments. Don't sacrifice extra student loan payments for consumer debt—clear the high-interest debt first.

The Numbers Don't Lie: More Comparisons

We ran multiple scenarios through our calculator:

Low Debt, Similar Rates

ScenarioAvalanche InterestSnowball InterestDifference
£8K total, 15-19% rates£1,423£1,487£64
£12K total, 12-17% rates£1,856£1,967£111
£15K total, 14-19% rates£2,734£2,876£142

Insight: With similar rates and lower balances, the difference is small. Go with whatever keeps you motivated.

High Debt, Varied Rates

ScenarioAvalanche InterestSnowball InterestDifference
£30K total, 5-24% rates£6,234£7,456£1,222
£45K total, 4-22% rates£9,456£11,234£1,778
£60K total, 3-26% rates£14,234£17,012£2,778

Insight: With varied rates and higher balances, Avalanche saves thousands. Worth the discipline.

Calculate your exact savings →

Your Action Plan

Step 1: List All Your Debts

Include balance, interest rate, and minimum payment for each.

Step 2: Calculate Both Scenarios

Use our Debt Payoff Calculator to see the actual numbers.

Step 3: Assess Your Psychology

Be honest: Will you stick with the optimal plan, or do you need quick wins?

Step 4: Pick Your Strategy

  • Big rate differences + discipline = Avalanche
  • Need motivation + similar rates = Snowball
  • Not sure = Hybrid (one quick win, then Avalanche)

Step 5: Automate Everything

Set up Direct Debits and standing orders so you don't rely on willpower.

Common Mistakes to Avoid

1. Only Paying Minimums

Minimum payments are designed to keep you in debt forever. A £10,000 credit card at 20% with minimum payments takes 25+ years to pay off.

2. Not Including All Debts

Be honest about everything: credit cards, store cards, catalogue debt, overdrafts, car finance, personal loans.

3. Ignoring 0% Balance Transfers

That 0% balance transfer card? It's not really 0%—the rate jumps to 21%+ when the promotional period ends. Set a calendar reminder and plan accordingly.

4. Raiding Your Emergency Fund

Don't put your emergency fund toward debt. One surprise expense puts you right back on credit cards.

5. Stopping at 90%

The last debt feels endless. Push through. The final payoff is the most important one.

Calculate Your Debt Payoff Strategy

See exactly how much you'll save with each method. Input your debts and compare:

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The Bottom Line

Avalanche saves more money. Snowball creates more motivation.

For most people with significant high-interest debt, Avalanche is the mathematical winner. But if you've failed at debt payoff before, Snowball's quick wins might be worth the extra interest.

The real answer? The best method is the one you'll actually finish.

Run your numbers:

The day you make your last payment, none of this debate will matter. You'll just be free.