How is child support calculated in Australia?

Child support in Australia is calculated using a formula based on both parents' adjusted taxable incomes, the number and age of children, and each parent's share of care. Each parent's income above a self-support amount ($29,043 in 2025-26) is combined, and the cost of children is estimated as a percentage of that combined income. Each parent's share of costs is proportional to their income, with offsets applied based on how many nights they care for the children.

What income is used to calculate child support?

Child support uses your adjusted taxable income (ATI), which includes your taxable income plus reportable fringe benefits, target foreign income, net investment losses, tax-free government pensions, and reportable superannuation contributions. This is broader than the taxable income on your tax return.

How does shared care affect child support payments?

Shared care significantly affects child support. If you have less than 14% care (fewer than 52 nights per year), you receive no cost offset. At 14-34% care, you receive a 24% cost offset. Regular care of 35-47% gives an increasing offset starting at 25%. Equal shared care (48-52%) provides a 50% offset but reduces the cost percentage used in the formula.

What is the minimum child support payment in Australia?

The minimum annual rate of child support is approximately $500 per year (about $19.23 per fortnight). This applies when the formula assessment produces a lower amount but there is still a liability. Parents on very low incomes or government payments may be assessed at this minimum rate.

Can I change my child support amount?

Yes. You can apply to Services Australia for a change of assessment if you believe special circumstances exist, such as high costs for a child's medical needs, school fees, or travel for contact. You can also make a private agreement (binding or limited) with the other parent. If your income changes significantly, Services Australia will reassess your liability when new tax returns are lodged.

Child Support Calculator

Estimate your Australian child support payment for 2026. Enter both parents' incomes, number of children, and care percentage to see how much you may pay or receive.

Last verified: 30 March 2026

Child Support Calculator Guide: How Payments Are Calculated

The child support formula in Australia follows an 8-step process using combined income, percentage of care, and cost of children tables. We explain every step with worked examples at various incomes.

Child Support Australia 2026: How Much?

Child support is based on both parents' incomes, care percentage, and number of children. Here's how the formula works in plain English.

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General information and estimates only — not financial, tax, or legal advice. Always verify with a licensed adviser or the ATO.

Child Support Calculator

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