Working out child support using the basic formula

The basic formula applies to parents with 1 child support assessment and no other dependent children. This is the formula we use for most child support assessments.

The 8 steps of the basic formula are:

StepActionThis step relates to...
1We calculate each parent's child support income, which is a parent's adjusted taxable income minus a self-support amount.Income
2We add both parents' child support incomes together to get a combined child support income.Income
3We divide each parent's individual child support income by the combined child support income to get an income percentage for each parent.Income
4We work out each parent's care percentage of the child using the care and cost table.Care
5We work out each parent's cost percentage of the child using the care and cost table.Care
6

We subtract the cost percentage from the income percentage for each parent. The result is called the child support percentage.

  • If it is a negative percentage, that parent is assessed to receive child support because their share of the costs of raising the children is more than met by the amount of care they are providing
  • If it is a positive percentage, that parent is assessed to pay child support because they are not meeting their entire share of the costs of the child directly through care. We go on to steps 7 and 8 using only the positive child support percentage.

If you have different care arrangements for various children, you might have different child support percentages for each child.

Child support percentage
7We work out the costs for each child based on the parents' combined child support income using the cost of children table.Costs of children
8We get the final child support payable by multiplying the positive child support percentage by the costs of the child. This final figure is the child support amount the paying parent needs to transfer to the other parent.Child support payable

The care and cost table

Child support payments reflect each parent's percentage of care and how much it costs parents to care for their children.

Read more about how your percentage of care affects your child support.

Child support care percentageEqual to number of nights a yearEqual to number of nights a fortnightCare levelChild support cost percentage
0–13%0–51 nights1 nightBelow regular careNil
14–34%52–127 nights2–4 nightsRegular care24%
35–47%128–175 nights5–6 nightsShared care25% plus 2% for every percentage point over 35% of care
48–52%176–189 nights7 nightsShared care50%
53–65%190–237 nights8–9 nightsShared care51% plus 2% for every percentage point over 53% of care
66–86%238–313 nights10–12 nightsPrimary care76%
87–100%314–365 nights13–14 nightsAbove primary care100%

Costs of children

The child support formula recognises the cost of raising children is different in households with different income levels, numbers of children and children of different ages.

Under the formula, the costs of raising children are calculated according to the combined income of both parents after a self-support amount is deducted. The costs are divided between the parents according to their share of the combined income.

The costs of children, determined by independent research, represent 'net' costs after Family Tax Benefit is taken into account.

Costs of children tables 2014

Children aged 12 years and under

Parents' combined child support income1 child2 children3 or more children
$0 to $35,285117c for each $124c for each $127c for each $1
$35,286 to $70,5692$5,998 plus 15c for each $1 over $35,285$8,468 plus 23c for each $1 over $35,285$9,527 plus 26c for each $1 over $35,285
$70,570 to $105,8543$11,291 plus 12c for each $1 over $70,569$16,583 plus 20c for each $1 over $70,569$18,701 plus 25c for each $1 over $70,569
$105,855 to $141,1384$15,525 plus 10c for each $1 over $105,854$23,640 plus 18c for each $1 over $105,854$27,522 plus 24c for each $1 over $105,854
$141,139 to $176,4235$19,053 plus 7c for each $1 over $141,138$29,991 plus 10c for each $1 over $141,138$35,990 plus 18c for each $1 over $141,138
$176,423 and over6$21,523$33,520$42,341

Children aged 13 years and over

Parents' combined child support income1 child2 children3 or more children
$0 to $35,28523c for each $129c for each $132c for each $1
$35,286 to $70,569$8,116 plus 22c for each $1 over $35,285$10,233 plus 28c for each $1 over $35,285$11,291  plus 31c for each $1 over $35,285
$70,570 to $105,854$15,878 plus 12c for each $1 over $70,569$20,113 plus 25c for each $1 over $70,569$22,229 plus 30c for each $1 over $70,569
$105,855 to $141,138$20,112 plus 10c for each $1 over $105,854$28,934 plus 20c for each $1 over $105,854$32,815 plus 29c for each $1 over $105,854
$141,139 to $176,423$23,640 plus 9c for each $1 over $141,138$35,991 plus 13c for each $1 over $141,138$43,047 plus 20c for each $1 over $141,138
$176,423 and over$26,816$40,578$50,104

Children of mixed age

Parents' combined child support income1 child2 children3 or more children
$0 to $35,285N/A26.5c for each $129.5c for each $1
$35,286 to $70,569N/A$9,351 plus 25.5c for each $1 over $35,285$10,409 plus 28.5c for each $1 over $35,285
$70,570 to $105,854N/A$18,348 plus 22.5c for each $1 over $70,569$20,465  plus 27.5c for each $1 over $70,569
$105,855 to $141,138N/A$26,287 plus 19c for each $1 over $105,854$30,168 plus 26.5c for each $1 over $105,854
$141,139 to $176,423N/A$32,991 plus 11.5c for each $1 over $141,138$39,518 plus 19c for each $1 over $141,138
$176,423 and overN/A$37,049$46,222

1. 0.5 times MTAWE

2. MTAWE

3. 1.5 times MTAWE

4. 2 times MTAWE

5. 2.5 times MTAWE

6. Cost of children do not increase above this cap