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.

1.1.M.50 Multi-case child costs

Definition

Multi-case child costs are used to calculate the multi-case allowance (1.1.M.30) and the multi-case cap (1.1.M.40). The multi-case child costs are the costs of each of a parent’s (1.1.P.10) child support (1.1.C.60) children (in all of their child support cases (1.1.C.80)) based on the parent’s income only.

The multi-case cost of each child is calculated as if all the child support children were the same age as that child. To work out this cost:

  • work out the total number of the parent's child support children
  • look up the parent's (individual) income and the age of the child on the relevant COTC (1.1.C.210) Table (2.4.2) to find what all the children would cost if they were all the same age
  • divide this amount by the total number of the parent's child support children.

Example: In 2024, Amari has 3 children and 2 child support cases. In case 1, child support needs to be assessed for Soraya aged 15, and Estelle aged 12. In case 2, child support needs to be assessed for Leigh aged 6. Amari has ATI (1.1.A.20) of $80,000 and child support income (1.1.C.120) of $51,537 for the purposes of calculating multi-case child costs (ATI less self-support amount).

StepAmari’s multi-case child costs
Calculate child support income

Calculate child support income

  • ATI less:
    self-support amount (1.1.S.20)
    relevant dependent child (1.1.R.60) amount
  • ATI of $80,000 −
    self-support amount ($28,463)
    relevant dependent child amount (not applicable)

CHILD SUPPORT INCOME
$80,000 − $28,463
= $51,537

Calculate multi-case child costs
Work out the total number of the parent’s child support childrenAmari has 3 children

For each child, find what all the children would cost if they were all the same age

  • use the parent’s child support income
  • use the COTC Table (2024)
  • Costs of Soraya (15 years old)
    Costs for 3 children aged 13+
    ($51,537 − $42,695) x 31% + $13,662
    = $16,403
  • Costs of Estelle (12 years old)
    Costs for 3 children aged 0 to 12
    ($51,537 − $42,695) x 26% + $11,528
    = $13,827
  • Costs of Leigh (6 years old)
    Costs for 3 children aged 0 to 12
    ($51,537 − $42,695) x 26% + $11,528
    = $13,827
Divide the costs by the number of child support children
  • Soraya’s multi case child costs
    $16,403 ÷ 3 = $5,468
  • Estelle’s multi case child costs
    $13,827 ÷ 3 = $4,609
  • Leigh’s multi case child costs
    $13,827 ÷ 3 = $4,609

Act reference: CSA Act section 5(1)-‘multi-case child costs’, section 47 Working out multi-case allowances

Policy reference: CS Guide 2.4.9 Formulas when a parent has multiple child support cases (Formulas 3 & 4)

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