KiwiSaver for Children Calculator

How this calculator works

The calculator compounds your monthly contribution at your chosen fund's expected annual return, applied monthly, from your child's current age up to 18, and then continues at the same monthly rate and return through to your second milestone age if you set one beyond 18. Once your child reaches 18, the calculator adds the annual government contribution for each full KiwiSaver year that follows, at 25c per $1 of contributions made in that year, capped at $260.72, matching the real member tax credit rule that this top-up is not available to members under 18. The result is split into three parts: the money your family actually paid in, the investment growth that compounding added on top, and the government contribution added from age 18 onward, so it is clear how much of the final balance is genuinely "free money" versus family savings.

Worked example

Take a newborn whose family contributes $50 a month into a Growth fund, assumed to return 4.5% a year net of fees and tax. From birth to 18, that is 216 monthly contributions of $50, growing at 4.5% a year compounded monthly. By the time the child turns 18, the account holds about $16,743.40. Of that, the family contributed exactly $10,800.00 over 18 years, investment growth contributed $5,793.40, and the government added $150.00 in the single KiwiSaver year the child turned 18, since $50 a month is $600 a year in contributions, and 25% of $600 is $150 (below the $260.72 cap, which would need $1,042.86 of contributions in that year). If the same $50 a month keeps going after 18, by age 25 the balance grows to about $29,061.63, made up of $15,000.00 in family contributions, $12,861.63 of investment growth, and $1,200.00 in government contributions across the eight years from 18 to 25.

Why starting early matters

Starting from birth rather than delaying a few years makes a real difference, and not just because more months of contributions go in. Contributing the same $50 a month into the same Growth fund but starting at age 5 instead of birth means only 13 years of contributions by 18, or $7,800.00 in total, and a projected balance at 18 of about $10,723.71. That is $6,019.69 less than starting from birth, even though the family only contributed $3,000.00 less. The remaining $3,019.69 of the gap is extra investment growth, earned purely because the money had five more years inside the fund to compound. The earlier money goes in, the longer it has to work, which is the core reason a small, steady contribution from birth outperforms a larger contribution started later for the same total outlay.

Government contributions and children

The KiwiSaver government contribution, officially the member tax credit, is one of the few parts of KiwiSaver where a child's account is genuinely treated differently to an adult's. Inland Revenue only pays this top-up to members aged 18 or over, so no matter how much a parent, grandparent or other family member contributes to a child's account before their 18th birthday, none of it attracts the government's 25c-per-$1 match. The full $260.72 maximum requires $1,042.86 of contributions within a single KiwiSaver year (1 July to 30 June), and the contribution is not paid at all once a member's income exceeds $180,000. This calculator applies the government contribution only from the KiwiSaver year in which the child turns 18, which is a reasonable approximation since actual eligibility depends on the exact date within that year that the birthday falls.

Opening a KiwiSaver account for a child

A parent or legal guardian can open a KiwiSaver account for a child of any age, including a newborn, directly with a provider, using the child's own IRD number. The account belongs to the child, but the signing parent or guardian manages it, including choosing the provider and fund type, until the child turns 18. Because a child has no employer and no PAYE income, there is no compulsory contribution rate to set. Contributions are entirely voluntary, and anyone in the family can make them, usually by automatic payment or direct credit using the KiwiSaver reference number the provider supplies. It is worth telling the provider the child's correct prescribed investor rate (PIR), typically the lowest 10.5% rate for a child with no other income, since accounts default to the top 28% rate if a PIR is not supplied, which would overtax a child's investment earnings.

Using it for a first home later

A child enrolled in KiwiSaver from a young age will typically clear the standard first-home withdrawal rules well before they need to use them. From age 18, a member can withdraw most of their KiwiSaver balance to help buy a first home to live in, provided they have been a KiwiSaver member for at least 3 years, which a child signed up at birth or in early childhood will have satisfied many years before turning 18. Member, employer and government contributions, plus the investment returns on them, are generally available to withdraw, while a minimum of $1,000 must remain in the account. For the exact amount available and the full eligibility test, see our dedicated KiwiSaver First Home Withdrawal Amount Calculator and KiwiSaver First Home Withdrawal Calculator.

What this calculator assumes

• The same monthly contribution continues at the same dollar amount for the whole period, with no increases or gaps.
• A flat annual return for the selected fund type, compounded monthly, with no year-to-year market ups and downs.
• The government contribution applies from the KiwiSaver year in which the child turns 18, calculated on the full annual contribution for that year and every year after, up to the $260.72 cap.
• The member's income while receiving the government contribution stays below the $180,000 cutoff.
• Results are a projection based on the figures you enter, not a forecast, a guarantee of investment performance, or financial advice.

Who this calculator is for

This is for parents, grandparents and other family members deciding whether, and how much, to contribute to a child's KiwiSaver account, and wanting to see the real difference that starting early and choosing a fund type can make by the time the child turns 18 or reaches an older milestone such as a first home. It is also useful for financial mentors explaining compounding to a family, and for anyone who has been given, or is considering giving, an occasional lump sum into a child's account and wants to see what it could become.

Frequently Asked Questions about KiwiSaver for children

Can a baby or child have a KiwiSaver account in New Zealand?

Yes. A parent or legal guardian can sign a child of any age up to a KiwiSaver scheme, including a newborn baby. The account is legally the child's, but a parent or guardian manages it and makes decisions on the child's behalf until they turn 18.

Do children get the KiwiSaver government contribution?

No, not until they turn 18. The government contribution, officially called the member tax credit, is only paid to members aged 18 or over. It matches 25c for every $1 of member contributions made in a KiwiSaver year (1 July to 30 June), up to a maximum of $260.72 a year, which requires $1,042.86 of contributions in that year. Money contributed on a child's behalf before they turn 18 does not attract this top-up, no matter how much is paid in.

Does a child's KiwiSaver account get employer contributions?

Almost never. Employer contributions only apply where a member is an employee earning PAYE income under a KiwiSaver-eligible employment agreement, which does not apply to most children. A child's account grows purely from whatever family members choose to contribute, plus investment returns, until the child is old enough to work and contribute themselves.

How much can I contribute to a child's KiwiSaver account?

Any amount, at any frequency you like. Because a child has no employer and no compulsory contribution rate, contributions are entirely voluntary lump sums or regular payments made directly to the provider, unlike an adult employee's fixed percentage of salary.

Can grandparents or other family members contribute to a child's KiwiSaver?

Yes. Anyone can make a voluntary contribution to a KiwiSaver member's account, including a child's, usually by direct credit or automatic payment using the member's KiwiSaver reference number supplied by the provider.

What tax rate applies to a child's KiwiSaver investment earnings?

KiwiSaver funds are taxed each year at the member's prescribed investor rate (PIR), which is based on taxable income. A child with no other income typically qualifies for the lowest 10.5% rate. If a PIR is not supplied to the provider, the default rate applied is 28%, so it pays to give the provider the child's IRD number and correct PIR.

Can my child use their KiwiSaver for a first home once they turn 18?

Yes, provided the standard first-home withdrawal rules are met: the member must be at least 18, have been a KiwiSaver member for at least 3 years, and be buying a first home to live in. A child enrolled young will usually clear the 3-year membership test well before 18. A minimum of $1,000 must stay in the account after the withdrawal.

What fund type suits a child's KiwiSaver account?

That depends on your own risk tolerance and how the money will eventually be used. With a horizon of well over a decade until the child turns 18, many parents lean towards a Growth or Aggressive fund rather than Conservative, but this calculator lets you compare all four standard fund types and is not a substitute for advice from a licensed financial adviser.

Related calculators

• KiwiSaver Government Contribution Eligibility Calculator: check the exact top-up your child (or you) can claim once eligible from 18.
• KiwiSaver First Home Withdrawal Amount Calculator: work out how much of the balance can actually be withdrawn for a first home.
• KiwiSaver First Home Withdrawal Calculator: check eligibility for the first-home withdrawal in full.
• KiwiSaver Retirement Projection Calculator: project a balance all the way to age 65 once your child is working.
• KiwiSaver Contribution Rate Calculator: compare employee contribution rates from 3.5% to 10% once your child starts earning.

Official NZ sources

This calculator is built from primary New Zealand sources. Always confirm current figures against the official source for your situation:

• Inland Revenue (IRD): KiwiSaver overview, member tax credit and withdrawal rules
• Inland Revenue (IRD): prescribed investor rates (PIR) for KiwiSaver and other PIEs
• Financial Markets Authority: KiwiSaver Fund Update return assumptions
• Sorted (Te Ara Ahunga Ora, Retirement Commission): KiwiSaver guidance for families