2.4.6 The costs of the child
Context
The child support formulas calculate the costs of the child to determine how the costs of each child in a child support assessment will be shared by both parents (either by care and/or the payment of child support).
Act references
CSA Act section 5, section 46, section 47, section 55E to section 55HA, Schedule 1
On this page
 The Costs of the Children Table
 Ages of the children
 Number of children
 Costs of the child  the basic formula method
 Costs of the child  multiple case method
 Costs of the child  relevant dependent child amount
The Costs of the Children Table
The Costs of the Children Table is used to calculate the:
 costs of the children (sections 55F55HA)
 multicase child costs (more information is available at 2.4.9), and
 relevant dependent child amount (2.4.4.20).
The Costs of the Children Table (Schedule 1) identifies the costs of the children in the assessment based on the number and age of the children in the assessment, and parental income which may either be:
 combined child support income (child support formulas 1, 2, 3 and 4 use the income of both parents), or
 one parent's child support income (child support formulas 5 and 6 only uses the income of 1 parent).
Parents' combined child support income or parent's child support income  

Fraction of MTAWE  0 to 0.5  0.5 to 1  1 to 1.5  1.5 to 2  2 to 2.5  Over 2.5 
Child support children  Costs of the children  
All children aged 0 to 12 years  
1 child  17%  15%  12%  10%  7%   
2 children  24%  23%  20%  18%  10%   
3 children  27%  26%  25%  24%  18%   
All children aged 13+ years  
1 child  23%  22%  12%  10%  9%   
2 children  29%  28%  25%  20%  13%   
3 children  32%  31%  30%  29%  20%   
At least 1 child aged 0 to 12 years and 1 child aged 13+ years  
2 children  26.5%  25.5%  22.5%  19%  11.5%   
3 children  29.5%  28.5%  27.5%  26.5%  19%   
The Costs of the Children Table is divided into columns, with each column representing an income bracket that is a fraction of the annualised MTAWE amount (2.4.2). If the income used to calculate the costs of the child is greater than 2.5 times MTAWE, then the costs are capped at the amount in the last column of the Costs of the Children Table.
The Costs of the Children Table is updated annually on 1 January and the costs are adjusted according to the updated annualised MTAWE amount. The updated Costs of the Children Table is used when making assessments for child support periods that start in that calendar year.
The current Costs of the Children Table (and previous 2 calendar years) can be found at 2.4.2, and historical tables are available at 2.4.13.
Example: The parents' combined child support income is $210,000, for a child support period starting 6 April 2023. There are 2 children aged 13 and over. The costs of the children are capped at $47,451, the number in the last column of the '2 children' row in the table for older children (13+ years).
Ages of the children
The Costs of the Children Table is divided into:
 children aged 0 to 12 years
 children aged 13+ years, and
 children of mixed age (where child support case has children aged 0 to 12 years, and 13+ years).
The costs of the children for a day in a child support period are calculated by identifying the age of the children for that day (section 55G(4)). If a child will turn 13 within the child support period the costs of the child will be calculated differently for the periods before and after the child's 13th birthday.
Example: Sam and Maria have 3 children, Alex aged 12, Nicholas aged 9 and Michael aged 8. The child support period starts on 6 September 2020. Alex's 13th birthday is on 12 November 2020.
The costs of the children are calculated using the table for 3 younger children (0 to 12 years) for the period 6 September to 11 November 2020. For the period 12 November 2020 to 5 December 2021 the costs are calculated using the mixed age amounts in the Costs of the Children Table.
Number of children
The Costs of the Children Table determines the costs for up to 3 children in an assessment.
Where there are 4 or more children, the same costs as for 3 children are used. When calculating costs for more than 3 children, the ages of the oldest 3 children are used (section 55G(4)).
When there is more than one child in an assessment, the costs of each children will be the total of the costs of the children divided by the actual number of children. This includes when there are children of mixed age, or where there are 4 or more children in the case.
Example: Ivan and Peta have 4 children, Adam aged 16, Deborah aged 15, Bristol aged 13 and Peta aged 8. The costs of the children are calculated using the ages of the 3 eldest children. As the 3 eldest children are aged 13 and over, the 'children aged 13+ years' section in the Costs of the Children Table is used. The costs of each child will be the total costs of the children divided by the actual number of children, which is 4.
Costs of the child  the basic formula method
The method used to work out the costs of the children using the Costs of the Children Table, are (section 55F):
Step  Methodology  Example 

Calculate the costs of the children  
Step 1 – Child support income range  Locate the appropriate child support income bracket (column).  The parents' combined child support income is $86,000. 
Step 2 – Number of children  Determine if there are 1, 2 , 3 or more children and identify the correct row.
If there is 4 or more children, identify the 3 oldest children. 
There are 4 children aged 17, 15, 10 and 8.
The 3 oldest children are aged 17, 15 and 10. 
Step 3 – Ages of children  Identify the ages of the children  all under 13, all 13+ years or of mixed ages. Go to the corresponding range (box).  The 3 children are of mixed age – one child is aged under 13, and 2 children are aged 13+. 
Step 4 – Calculate costs of the children  Follow the instructions in the box to determine the costs of the children.  Costs of the children = $23,932 + (($86,000 − $82,525) × $0.275) = $23,932 + ($3,475 × $0.275) = $23,932 + $1,303 (rounded) = $24,888 
Calculate the costs of the child  
Step 5 – Calculate the costs of the child  Calculate the costs of each individual child by dividing Step 4 by the number of children in the assessment.  Costs of the child = $24,888 ÷ 4 = $6,222 per child 
The amount calculated is rounded, to the nearest dollar (below 49.5c rounded down, 49.5c and above rounded up), to a dollar figure at each step.
Costs of the child  multiple case method
If one or both parents has multiple child support cases, the multiple case method calculates the costs of a child in a child support case by treating all children in the relevant case as the same age as that child (section 55HA). The mixed age range of the Costs of the Children Table is not used in the multiple case method. See topic 2.4.9 for further information about working out the amount of child support payable where one or both parents have multiple child support cases.
The steps to be used for each case, using the Costs of the Children Table, are:
Step  Methodology  Example 

Step 1 – Child support income range  Locate the appropriate child support income bracket (column).  The combined child support income is $86,000. 
Step 2 – Number of children  Identify the number of children in the case for which the costs are being determined.  The child support case has 3 children, Diane aged 12, Felix aged 14 and Rossana aged 15. 
Step 3 – Ages of children  For each child in the case, identify the age of the child.  Diane is 12 years of age. 
Step 4 – For each child, calculate costs of the child  For each child in the case, calculate the cost of the child as though all of the children in the case were the same age as that child.  For Diane, assume the case has 3 children aged 0 to 12 years.
Costs of the children = $21,869 + (($86,000 − $82,525) × $0.25) 
Repeat Steps 3 to 4 to work out the costs of each other child in the case.  Repeat Steps 3 and 4 to calculate the costs for Felix and Rossana (both aged 13+).
Costs of the children = $25,995 + (($86,000 − $82,525) × $0.30) Costs of the child (Felix) = $27,037.50 ÷ 3 = $9,013 

Step 5 – Total costs of the children for the case  The cost of the children for the case is $25,605.


Repeat Steps 1 to 5 for each child support case. 
Example: In 2020, Beatrix has 2 child support cases. In case 1, the parents' combined child support income is $86,000 and there are 2 children, Phoebe aged 4 and Anthony aged 7. In case 2, the parent's combined child support income is $101,000 and there are 2 children, Elvira aged 9 and Bart aged 15.
Case 1  Case 2 

The costs of Phoebe are the total of $18,030 plus 20c for each $1 over $76,726. Costs of the children = $18,030 + (($86,000 − $76,726) × $0.20) Costs of Phoebe = $9,943 ($19,885 divided by 2 children and rounded) The same calculation is used to work out the costs of the child Anthony = $9,943. 
The costs of Elvira are the total of $18,030 plus 20c for each $1 over $76,726 (costs of 2 children the same age as Elvira). Costs of the children = $18,030 + (($101,000 − $76,726) × $0.20) Costs of Elvira = $11,443 ($22,885 divided by 2 children and rounded) The costs of Bart are the total of $21,867 plus 25c for each $1 over $76,726 (costs of 2 children the same age as Bart). Costs of the children = $21,867 + (($101,000 − $76,726) × $0.25) Costs of Bart = $13,968 ($27,936 divided by 2 children) 
Costs of the child  relevant dependent child amount
If a parent has a relevant dependent child in their care the cost of the parent caring for that child is taken into account in calculating their child support assessment.
See 2.4.7 for information on what a relevant dependent child is. See 2.4.4.20 for information on how the relevant dependent child amount is used to calculate a parent’s child support income. See 2.9.5 for information about amending an assessment to recognise a relevant dependent child.
Only the initial child support income of the parent who has the relevant dependent child is used to calculate the costs of the relevant dependent child.
A parent's relevant dependent child amount is the total of the amounts worked out for each relevant dependent child of the parent using the following steps (section 46).
Step  Methodology  Example 

Step 1 – Calculate initial child support income  Deduct the selfsupport amount from the parent's ATI.  Sungsoo has an ATI of $66,000. $66,000 less $27,508 = $38,492. 
Step 2 – Percentage of care for the relevant dependent child (2.4.5)  Work out the parent's percentage of care for the child. Note: A parent who lives fulltime with a relevant dependent child has 100% care of that child, even if they also live with a new partner. 
Sungsoo has 2 relevant dependent children: Abigail aged 3 and Suellen aged 6. Sungsoo has 100% care of Abigail and Suellen. 
Step 3 – Cost percentage for relevant dependent child (2.4.5)  Work out the parent's cost percentage for the child.  The cost percentages are 100% for Abigail and Suellen. 
Step 4 – Costs of the child  Work out the costs of the child using the 'basic formula method' described above, using the parent's initial child support income only.  Costs of the children = 38,492 × 24% = $9,238 Cost of Abigail = $9,238 ÷ 2 = $4,619 Cost of Suellen = $4,619 As Sungsoo has a cost percentage of 100% for Abigail, the relevant dependent child amount is $4,619 (100% × $4,619). As Sungsoo has a cost percentage of 100% for Suellen, the relevant dependent child amount is $4,619 (100% × $4,619). 
Step 5 – Calculate the relevant dependent child amount    Sungsoo's relevant dependent child amount is $9,238 (the sum of each of the child amounts at Step 4). 
The new partner's income is not included in the calculation of the relevant dependent child amount.