What's the difference between KiwiSaver, Australian super and a US 401(k)?

Side by side

KiwiSaver

• You, from 3.5%
• Employer, at least 3.5%

Matched: the employer's share is tied to yours

Australian super

• You, if you choose to
• Employer, 12%

The employer must pay whether you contribute or not

US 401(k)

• You, from your wages
• Employer, if it chooses

Voluntary on both sides, and only if a plan is offered

They also open at different ages, which the last section sets out.

KiwiSaver: you and your employer, matched

KiwiSaver runs on matching. You choose a rate from your pay: Inland Revenue lists 3.5%, 4%, 6%, 8% or 10%, with 3.5% applying if you do not choose a higher one.

Your employer then has to match a minimum. Inland Revenue: "Your employer must contribute at least 3.5% of your gross earnings on top of your regular pay", with exceptions including being under 16, being over the age of eligibility, or not contributing yourself.

Two details that catch people. Your employer's contribution is taxed before it lands, so "the amount paid to your KiwiSaver scheme by your employer may be less than 3.5%". And if you stop contributing, your employer's obligation generally stops with it. The money is matched, not granted.

There is also a temporary rate reduction, which lets someone keep contributing at 3% for between three and twelve months.

Australian super: your employer's obligation, not yours

This is the big structural difference. In Australia the duty sits with the employer regardless of what the employee does.

The ATO states it plainly: "As an employer, it's compulsory to pay your eligible employees SG at least 4 times a year", and "From 1 July 2025 this is 12% of their ordinary time earnings".

So an Australian employee who never thinks about super still accumulates it. Someone in New Zealand who is not contributing from their pay gets nothing from their employer either, because the two are tied together.

The ATO also notes that for earnings paid from 1 July 2026, new "Payday Super" rules apply, which change when contributions must be made rather than how much.

US 401(k): only if it is offered

A 401(k) is a feature of an employer's plan. The IRS describes it as "a feature of a qualified profit-sharing plan that allows employees to contribute a portion of their wages to individual accounts", and adds that "employers can contribute to employees' accounts".

Note the word can. There is no equivalent of the Australian 12% or the New Zealand match. An employer may match, may contribute regardless, or may do neither. And if your employer runs no plan, there is no 401(k) to join at all, which is why individual retirement accounts exist alongside them.

When each one opens

They unlock on different rules, not just different numbers.

KiwiSaver: 65. Clause 4 of the scheme rules locks it until the New Zealand superannuation qualification age.

Australian super: 60 or 65. The ATO says you can withdraw when you "turn 65 years old, even if you're still working", or when you "reach your preservation age and choose to retire". Preservation age is 60 for anyone born from 1 July 1964.

US 401(k): 59½, and that is a tax threshold rather than a lock. The IRS treats withdrawals before then as early distributions carrying "an additional 10% early withdrawal tax unless an exception applies".

There is a fuller guide on the ages, including what happens to money that has moved between countries.

What this guide does not tell you

It does not cover how each one is taxed, which differs at every stage and in every country.

It also leaves alone the government contribution to KiwiSaver, Australia's contribution caps and co-contribution, employer matching formulas in the United States, what happens to any of them when you change countries, and how each is invested.

The contribution rates above are the ones in force on the dates the sources carry. All three countries change them, and New Zealand's went up on 1 April 2026, so check before relying on a number.