IRD Child Support Calculator NZ 2026: How Child Support Is Calculated

If you are looking for an IRD child support calculator, you can use Inland Revenue’s official online tool to estimate how much child support you may need to pay or receive in New Zealand.

The calculation is not based on income alone. Inland Revenue considers factors such as each parent’s relevant income, the number and ages of the children, recognised care arrangements, other dependent children and other child support obligations.

This guide explains how the IRD child support calculator works, what information you need, how shared care affects the calculation, the current 2026–2027 child support rates, and what to do if your circumstances are more complicated than a standard calculation.

What Is the IRD Child Support Calculator?

The IRD child support calculator is an online tool provided by Inland Revenue to help parents and carers estimate child support in New Zealand.

It is designed around the New Zealand child support formula. The calculator uses information about income, children and care arrangements to produce an estimated result.

Inland Revenue explains that the calculator is only as accurate as the information entered. If you do not know the other parent's income, you can use your best estimate when using the calculator.

You can access the official calculator directly from the Inland Revenue child support calculator page.

The official calculator is useful when you want to understand the potential amount before dealing with an assessment. However, the result should not automatically be treated as the final amount Inland Revenue will assess.

How Much Child Support Will I Pay or Receive?

There is no single child support amount that applies to every family. The IRD child support calculator considers the financial and care circumstances of the parents and children.

For example, two parents with the same income may have different child support results if their care arrangements or number of dependent children are different.

Likewise, a parent with a higher income does not necessarily pay a simple percentage of their salary. Inland Revenue applies the child support formula to the relevant circumstances.

How Does the IRD Child Support Calculator Work?

The IRD child support calculator follows the same broad principles used in Inland Revenue's formula assessment system.

The calculation considers the financial contribution expected from each parent and the costs associated with caring for the children.

Step 1: Work Out Each Parent's Relevant Income

Inland Revenue first determines the income used for the child support calculation.

If a person receives salary, wages, a benefit or other income taxed at source, Inland Revenue generally starts with taxable income from the last calendar year.

If the person files an IR3 individual income tax return, Inland Revenue generally starts with net income from two tax years ago and adjusts it for inflation.

The income rules can therefore be different from simply looking at a parent's current weekly salary.

Step 2: Apply Relevant Allowances

Inland Revenue then applies allowances that recognise certain living and family costs.

These can include:

• Living allowance
• Dependent child allowance
• Multi-group allowance

The result is the parent's child support income.

Step 3: Combine the Parents' Child Support Income

The child support income of both parents is combined.

This helps determine each parent's income percentage and how their financial contribution compares with the other parent.

Step 4: Consider Recognised Care

The formula does not look at income alone. It also considers how much ongoing care each parent provides.

This is known as recognised care.

Inland Revenue says a child generally needs to live with a parent or carer for at least 28% of the time, which is approximately 2 nights a week or 103 nights a year, for that care to be included in the formula.

A receiving carer generally needs at least 35% of ongoing daily care, or about 128 nights a year, to receive child support payments.

See the official IRD recognised care guidance for the current rules.

Step 5: Calculate the Child Support Amount

The income and care percentages are used with Inland Revenue's child expenditure tables to determine the amount of child support under a formula assessment.

This is why entering the correct care arrangements is particularly important when using an online calculator.

What Information Does the IRD Child Support Calculator Need?

Before using the IRD child support calculator, gather as much accurate information as possible.

• Your relevant income
• The other parent's relevant income
• Number of qualifying children
• Age of each child
• Number of nights each parent provides care
• Other dependent children
• Other child support obligations
• Relevant family circumstances

If you do not know the other parent's income, Inland Revenue allows users to enter their best estimate in the calculator.

However, the more accurate the information you enter, the more useful the resulting estimate is likely to be.

IRD Child Support Rates 2026–2027

The rates used for formula assessments are updated each year. The current child support year runs from 1 April 2026 to 31 March 2027.

These are the current published rates for the 2026–2027 child support year. Inland Revenue notes that living allowances and minimum child support rates are updated each year.

For the latest official figures, visit the IRD child support rates page.

Does the Child's Age Affect Child Support?

Yes. The age of the child can affect the amount used in the child support formula.

Inland Revenue publishes child expenditure tables that use different spending levels according to the age and number of children.

For the 2026–2027 child support year, Inland Revenue provides expenditure tables for children aged 12 and under and children aged 13 and over.

Child support can therefore change when a child reaches a different age category.

Inland Revenue also states that child support will be reassessed when a child turns 13.

You can review the current child expenditure tables on the official IRD website.

How Does Shared Care Affect Child Support?

Shared care can have a significant effect on the child support calculation.

The IRD child support calculator takes recognised care into account because the costs of raising a child can be shared between parents depending on how much ongoing care each provides.

For child support purposes, recognised care is generally based on the number of nights a child regularly lives with each parent.

If a child lives with each parent some of the time, both care and income can affect the result.

This means a parent with more overnight care does not automatically receive child support in every situation. The income percentages and care cost percentages are considered together.

For the official rules, see Sharing care of children – Inland Revenue.

What Happens If Your Income Changes?

A significant change in income can affect child support.

If you expect your income to fall by at least 15% from the income used in your assessment, you may be able to provide an income estimate to Inland Revenue.

This can be relevant to both a paying parent and a receiving carer.

For example, an income change could occur because of:

• Job loss
• Reduced working hours
• A significant reduction in business income
• A major change in employment
• Another substantial income change

Inland Revenue explains the current requirements on its page about child support income estimations.

Do not assume that a change in income automatically changes an existing assessment. The relevant Inland Revenue process needs to be followed.

Is the IRD Child Support Calculator Exact?

The IRD child support calculator provides an estimate rather than replacing an official Inland Revenue assessment.

The result depends on the information entered into the calculator. An official assessment may use information held by Inland Revenue and apply the relevant statutory rules to the circumstances.

This distinction is important if you are trying to understand why your own calculation differs from an official child support notice.

What If Your IRD Child Support Amount Looks Wrong?

If the amount shown on your child support notice is different from what you expected from the IRD child support calculator, first check the information used in the assessment.

Look at:

• Income information
• Children's ages
• Recognised care arrangements
• Other dependent children
• Other child support obligations
• Income estimates
• Dates relevant to the assessment

Inland Revenue advises people who believe something on a child support notice is wrong to contact Inland Revenue and discuss the options for getting the information corrected.

You can also read our IRD Contact Number NZ guide for general information about contacting Inland Revenue.

Can You Manage Child Support Through myIR?

Yes. myIR provides online access to a range of Inland Revenue services.

Depending on your circumstances, myIR can be used to manage child-support-related information and communicate securely with Inland Revenue.

You can access official myIR services through Inland Revenue.

If you are having difficulty understanding an IRD message or notice, you may also find our IRD Help NZ resources useful.

Common Mistakes When Using a Child Support Calculator

When using the IRD child support calculator, avoid relying on assumptions that are not supported by your actual circumstances.

Using the Wrong Income Figure

The income used for child support purposes may not simply be your current salary. Inland Revenue has specific rules for determining the relevant income.

Ignoring Shared Care

Entering an incorrect number of care nights can materially affect an estimate.

Forgetting Other Dependent Children

Other dependent children may affect the allowances used in the formula.

Assuming Child Support Is a Fixed Percentage

New Zealand's formula considers multiple factors rather than simply applying one percentage to a parent's salary.

Treating the Calculator Result as an Official Assessment

The online calculator is useful for estimation, but the final assessment is determined through Inland Revenue's assessment process.

When Should You Get Help With an IRD Child Support Matter?

The IRD child support calculator can be very useful for straightforward estimates. However, some situations are more complicated.

You may want help understanding the position if you are dealing with:

• A significant income change
• Complex shared-care arrangements
• Multiple children
• Children from different relationships
• Other child support obligations
• A disputed assessment
• Incorrect income information
• An IRD notice you do not understand
• A disagreement about recognised care
• Difficulty communicating with Inland Revenue

Related IRD Resources

• IRD Contact Number NZ – Find information about contacting Inland Revenue.
• Call IRD NZ – Options for contacting IRD and getting assistance.
• IRD Help NZ – Explore IRD-related guides and resources.
• Contact IRD Guru – Get in touch regarding an IRD-related matter.

Frequently Asked Questions About the IRD Child Support Calculator

What is the IRD child support calculator?

The IRD child support calculator is an online Inland Revenue tool that estimates how much child support you may pay or receive based on information such as income, children's details and recognised care.

How is child support calculated in New Zealand?

Child support is calculated using a formula that considers relevant parental income, allowances, children's ages, recognised care and child expenditure amounts.

Is the IRD child support calculator accurate?

The IRD child support calculator provides an estimate based on the information entered. The final amount may differ because Inland Revenue's official assessment can use information held by Inland Revenue and apply the applicable rules to your circumstances.

What income does the IRD child support calculator use?

The income used depends on the person's circumstances. Inland Revenue generally uses taxable income from the last calendar year for certain income types, while people who file an IR3 may have income from two tax years ago adjusted for inflation used in the calculation.

Does shared care reduce child support?

Shared care can affect child support because the formula considers recognised care. A child generally needs to live with a parent or carer for at least 28% of the time for that care to be included in the formula.

What is the minimum child support payment for 2026–2027?

For the child support year from 1 April 2026 to 31 March 2027, Inland Revenue lists the minimum annual child support rate as $1,211.

Can child support change if my income drops?

Potentially. If you expect your income to drop by at least 15% from the income used in your assessment, you may be able to provide an income estimate to Inland Revenue.

Can I use the calculator if I do not know the other parent's income?

Yes. Inland Revenue states that you can use your best estimate of the other parent's income when using the online calculator.

Does the child's age affect child support?

Yes. Inland Revenue's child expenditure tables use different spending levels based on children's ages and the number of children. Child support is also reassessed when a child turns 13.

Where can I find the official IRD child support calculator?

You can access the official IRD child support calculator through Inland Revenue's website.

Open the Official IRD Child Support Calculator

Final Takeaway: Use the IRD Child Support Calculator as a Starting Point

The IRD child support calculator is a useful starting point if you want to estimate child support in New Zealand.

The calculation is more than a simple percentage of income. Inland Revenue considers relevant income, allowances, children's ages, recognised care and other factors under the child support formula.

For the 2026–2027 child support year, the published living allowance is $30,557, the supported living payment allowance is $34,252 and the minimum annual child support rate is $1,211.

If you want an estimate, use the official calculator and enter the most accurate information available. If your circumstances are complicated or your official assessment differs substantially from your expectations, consider getting appropriate assistance to understand the position.