The Guides to Social Policy Law is a collection of publications designed to assist decision makers administering social policy law. The information contained in this publication is intended only as a guide to relevant legislation/policy. The information is accurate as at the date listed at the bottom of the page, but may be subject to change. To discuss individual circumstances please contact Services Australia. Other components of child support income


This topic contains explanations of the components used to calculate child support income, other than ATI (

Act references

CSA Act section 45, section 46, section 47


A parent's child support income is their:

Self-support amount

The self-support amount is the amount that is deducted from the parent's ATI for their own support. The amount is the same for both parents and is updated each year.

The self-support amount is worked out as follows:

  • ⅓ × Annualised MTAWE figure for the relevant June quarter (section 45)

The annual value of the self-support amount is included in the table of basic values in 2.4.2. The table of basic values also includes more information about the annualised MTAWE figure and the relevant quarter.

Relevant dependent child amount

If a parent has a relevant dependent child in their care, an amount is deducted from their ATI when working out their child support income. See 2.4.6 to see how the relevant dependent child amount is calculated. The amount deducted in calculating a child support income is the total of the amounts worked out for each relevant dependent child of the parent (section 46).

Multi-case allowance

If a parent has been assessed for the costs of the children of more than one relationship (that is, the parent has multiple child support cases) then a multi-case allowance is deducted from the parent's ATI when working out their child support income (section 47). See 2.4.9 Formulas 3 and 4 for information about how the multi-case allowance is calculated and for an explanation of how an assessment is calculated when one or both of the parents have multiple child support cases.

Last reviewed: