Debt Avalanche vs. Debt Snowball: Which Method Should You Use?
Two proven strategies for paying off debt. We compare the debt avalanche and debt snowball methods to help Australians choose the approach that suits them best.
The Two Methods in a Nutshell
When you have multiple debts, you need a strategy for allocating any extra repayment dollars. Two frameworks dominate personal finance:
Debt Avalanche: Pay minimum repayments on all debts. Throw every extra dollar at the highest interest rate debt first.
Debt Snowball: Pay minimum repayments on all debts. Throw every extra dollar at the smallest balance first, regardless of rate.
Both work. The question is which one works better for you.
The Debt Avalanche: Maximum Mathematical Efficiency
The avalanche method is mathematically optimal. By targeting the highest-rate debt first, you minimize total interest paid across all your debts.
Example — Australian scenario:
| Debt | Balance | Rate | Minimum |
|---|---|---|---|
| Credit card (CBA) | $4,200 | 21.74% | $84 |
| Personal loan | $9,500 | 12.5% | $220 |
| Car loan | $15,000 | 7.9% | $310 |
| HECS-HELP | $28,000 | CPI-indexed (~4%) | Automatic |
With $800/month total available, the avalanche would direct all extra money at the CBA card first. Once that is cleared, the freed-up $84 minimum plus any surplus goes to the personal loan, and so on.
Over 3-5 years, the avalanche will save hundreds to thousands of dollars in interest compared to the snowball.
Best for: People who are analytically motivated, who can sustain their plan without frequent "wins," and who have long-term discipline.
The Debt Snowball: Psychological Momentum
The snowball method — championed by Dave Ramsey — sacrifices some mathematical efficiency for psychological momentum. Eliminating small balances quickly creates wins that motivate you to continue.
Using the same example above, the snowball would target the CBA card first ($4,200 balance — same result here, coincidentally), then the personal loan ($9,500), then the car loan ($15,000).
Research from Harvard Business Review confirms that people who pay off the smallest balance first are statistically more likely to successfully eliminate all debts — because motivation compounds along with momentum.
Best for: People who have struggled to stick with a debt repayment plan before, who need visible progress to stay motivated.
The Australian Debt Landscape
Credit cards: Australia has some of the highest credit card interest rates in the developed world — the average is around 19-22%. Commonwealth Bank, ANZ, Westpac, and NAB all charge in this range on standard cards. These should always be tackled first regardless of which method you choose.
Buy Now Pay Later (BNPL): Afterpay, Zip, and Klarna are not interest-bearing in the traditional sense, but late fees and the temptation to overspend can make them costly. Clear BNPL balances in full each period.
Personal loans: Rates vary widely — from 7-8% through credit unions and neobanks (Up, Wisr) to 19%+ for unsecured personal loans through payday lenders. Know your rate.
HECS-HELP student debt: CPI-indexed (not interest-bearing in the conventional sense). Compulsory repayments kick in above $54,435 income. Voluntary HECS repayments make sense only if the CPI indexation rate exceeds your expected investment return — rarely the case when long-term equity returns average 7-10%.
Mortgages: Generally the lowest-rate debt you hold. Standard practice is to focus other debts first, then make extra mortgage repayments (use an offset account for maximum efficiency — offset balances reduce interest charged daily without locking money away).
A Simple Decision Framework
If your highest-rate debt is ALSO your smallest balance → either method gets you there first.
If you have: High rate + large balance → Avalanche wins mathematically
If you have: Low rate + small balance → Snowball wins psychologically
If you've tried and failed before → Snowball
If you're data-driven and disciplined → Avalanche
Combining Both Methods
A hybrid approach works well: if you have a small debt close to zero, pay it off first for a quick win (snowball logic), then switch to avalanche order. This is pragmatic, not cheating.
What About Super and Investing While Paying Debt?
A common Australian dilemma: should you put extra money toward debt repayment, or into super/investing?
Rule of thumb:
- If debt rate > your expected investment return (~7-10%) → prioritize debt
- If debt rate < expected investment return → consider investing alongside minimum repayments
- Always capture employer super (it is already happening at 11.5%)
- Always pay off credit cards (19-22% rate beats any investment return risk-adjusted)
- HECS/HELP: invest instead — the CPI-indexed rate is almost always below long-term investment returns
The perfect plan you stick to beats the optimal plan you abandon.
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