Debt Avalanche vs. Debt Snowball: Which Is Right for You?

Two Strategies, One Goal

When you have multiple debts competing for your extra dollars, you need a system. The two most widely recommended are:

Debt Avalanche: Pay minimums on everything. Direct all extra money to the highest interest rate debt first.

Debt Snowball: Pay minimums on everything. Direct all extra money to the smallest balance debt first.

Both work. The difference is mathematical optimality vs. psychological momentum.

The Debt Avalanche: Lowest Total Interest

The avalanche minimizes total interest paid over the life of your debts. Mathematically, it is the superior method.

New Zealand Example:

Debt	Balance	Interest Rate	Minimum Payment
Credit card (ANZ Visa)	$3,500	20.95%	$70
Personal loan	$7,000	13.9%	$165
Car loan	$12,000	9.9%	$280
Student loan	$18,000	0% (see below)	IRD deducted

With $800/month available, the avalanche directs everything extra at the ANZ Visa first. When the card is cleared, the freed-up payment rolls to the personal loan, then the car loan.

Over 3-5 years, this method saves hundreds to thousands in interest compared to other approaches.

Best for: Analytically motivated people who can stay disciplined without frequent wins.

The Debt Snowball: Psychological Wins

The snowball ignores interest rates and focuses on eliminating accounts quickly. Smallest balance first — regardless of rate.

In the NZ example above, the ANZ card ($3,500) is the smallest balance — so both methods coincide there. Next would be the personal loan ($7,000), then the car loan ($12,000).

Research consistently finds that people using the snowball method are more likely to fully eliminate their debts — because momentum and visible progress sustain motivation over a multi-year journey.

Best for: People who have tried and failed at debt repayment before; those who need visible wins.

The New Zealand Student Loan Reality

New Zealand student loans are a unique debt type: they charge 0% interest for New Zealand residents (the student loan base interest rate is the 10-year government bond rate — which for NZ residents has been effectively zero for years, though this may be subject to change).

The practical implication: do not prioritise student loan repayment over other debts or investing.

With a 0% interest rate, any extra dollar directed at the student loan has an opportunity cost — it could be in a KiwiSaver growth fund or Sharesies ETF account earning 7-10%.

The only exception: If you plan to leave New Zealand long-term, your NZ student loan becomes interest-bearing (at a significantly higher rate). In that case, repaying before emigrating is a priority.

Compulsory student loan repayments are deducted by IRD automatically via PAYE at 12 cents in the dollar above the repayment threshold ($22,828/year in 2024-25). These are not discretionary — factor them into your take-home pay calculation.

New Zealand Credit Card Rates

Major NZ bank credit cards typically charge:

• ANZ: 20.95%
• ASB: 20.95%
• BNZ: 20.95%
• Westpac: 19.95%
• Kiwibank: 19.99%

These are among the highest consumer interest rates in NZ. Credit card debt should always be the first discretionary target in both avalanche and snowball approaches.

Interest-free credit card offers: Some NZ banks (Gem Finance, Q Card) offer 0-6 month interest-free periods. These are useful only if you pay the balance in full before the promotional period ends — otherwise the back-dated interest applies.

Personal Loans in New Zealand

NZ personal loan rates range widely:

• Credit unions and neobanks: 8-12%
• Major banks: 12-17%
• Finance companies: 20-29%
• Payday/fast lenders: 29%+ (extremely high — avoid)

The lower the credit score and the less secured the loan, the higher the rate. Know your exact rate and factor it into your priority order.

Investing vs. Debt Repayment in NZ

With a 0% student loan, the NZ debt repayment decision is different from most countries:

Clear priority — pay off first:

• Credit cards (20% — guaranteed return beats any investment)
• Personal loans above 12%

Borderline — could argue either way:

• Personal loans at 8-12% vs. expected investment return of 7-10%

Invest instead:

• Student loans (0% — invest the extra dollars)
• Mortgage (rates typically 6-8% currently — borderline; maintain minimum repayments, use offset account if available)

A Practical Starting Recommendation

If you have a credit card balance alongside other debts, both the avalanche and snowball will direct you to the credit card first (highest rate AND often a manageable balance). You get the mathematical and psychological win simultaneously.

After that, choose based on your psychology: have you succeeded at multi-year plans before? Use avalanche. Have you tried and fallen off track? Use snowball.

The perfect plan you abandon costs infinitely more than the slightly suboptimal plan you complete.