Child support: how it works

Last checked: 31 October 2026

The short answer

Child support is money paid by one parent to help with the costs of raising a child. Services Australia works out the amount with a formula that looks at both parents' income and how much care each parent has. Parents can also make a child support agreement. If you think a decision is wrong, you can object within 28 days.

Key dates and time limits

• Tell Services Australia about changes in care within 28 days.
• Object to a decision within 28 days of getting the letter (90 days if you live overseas in a reciprocating country).
• Ask the Administrative Review Tribunal to review an objection decision within 28 days.
• To extend child support past 18 for a child in full-time secondary school, apply while the child is 17.

Step by step

1. 1

   Apply for an assessment

   You can apply online or call the Child Support enquiry line on 131 272. You must be a legal parent, or a non-parent carer with at least 128 nights of care a year. At least one parent must live in Australia.

2. 2

   Get your assessment notice

   Services Australia writes to both parents with the amount and the start date. Check every detail. The formula uses both parents' incomes and each parent's percentage of care.

3. 3

   Choose how it is paid

   With Child Support Collect, Services Australia collects and passes on payments. With Private Collect, parents manage payments themselves. If you have safety worries, ask to speak to a social worker.

4. 4

   Consider an agreement

   A limited child support agreement needs an assessment in place and must be at least the assessed amount. Legal advice is not required. A binding child support agreement can be for any amount, but both parents must get independent legal advice first.

5. 5

   If you disagree

   Call Services Australia first to talk it through. You can object to most decisions within 28 days using the Objecting to a Child Support decision form. If you disagree with the objection decision, you can apply to the Administrative Review Tribunal within 28 days. In special circumstances you can also apply to change your assessment.

6. 6

   When it ends

   An assessment usually ends when the child turns 18, unless it is extended to the end of the school year. It also ends for other reasons, such as the parents getting back together for 6 months or more, or a change in care.

Who can help

Forms and the law