Working out child support payments using the basic formula

The basic formula applies to parents with only one child support assessment.

Basic formula 8 steps

The 8 steps of the basic formula are:

Step Action This step relates to
1
Work out each parent’s child support income

We calculate each parent's child support income. This is a parent's adjusted taxable income minus a self support amount and any relevant dependant allowance. For more information about relevant dependant allowances, see child support assessments and second families.

A parent may be able to estimate their income. Read more about income used in calculating a child support assessment.

Income
2
Work out the parents’ combined income
We add both parents' incomes to work out a combined child support income. Income
3
Work out each parent’s income percentage
We work out each parent’s income percentage by dividing each parent's income by their combined total. Income
4
Work out each parent’s percentage of care for the child
We calculate each parent's percentage of care. Care
5
Work out each parent’s cost percentage for the child
We work out each parent's cost percentage using the care and cost table. Care
6
Work out each parent’s child support percentage for the child

We subtract the cost percentage from the income percentage for each parent. The result is called the ‘child support percentage’. The result will determine if a parent pays or receives child support.

If it’s a negative percentage, that parent is assessed to receive child support. This is because their share of costs for the child is more than met by the amount of care they provide.

If it’s a positive percentage, that parent is assessed to pay child support. This is because they’re not meeting their share of the costs for the child directly through care.

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

We go on to steps 7 and 8 using only the positive child support percentage.

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

Care and cost table

The percentage of care and its costs are incorporated into the child support payable amount. The cost percentage reflects the percentage of a child’s costs that a person meets directly through care.

Child support care percentage Equal to number of nights a year Equal to number of nights a fortnight Care level Child support cost percentage
0–13% 0–51 nights 1 night Below regular care Nil
14–34% 52–127 nights 2–4 nights Regular care 24%
35–47% 128–175 nights 5–6 nights Shared care 25% plus 2% for every percentage point over 35% of care
48–52% 176–189 nights 7 nights Shared care 50%
53–65% 190–237 nights 8–9 nights Shared care 51% plus 2% for every percentage point over 53% of care
66–86% 238–313 nights 10–12 nights Primary care 76%
87–100% 314–365 nights 13–14 nights Above primary care 100%

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

Costs of children

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

Under the formula, we deduct an amount for each parent to support themselves. The costs of raising children are calculated according to the remaining combined child support income of both parents. The costs are divided between the parents according to their share of the combined income.

The costs of children table represents net costs after Family Tax Benefit is taken into account.

Figures below are for child support periods beginning in 2017.

Read more about costs of children for earlier calendar years in the Child Support Guide.

Children aged 12 years and under

Parents' combined child support income 1 child 2 children 3 or more children

$0 to $36,231

$36,231 is 0.5 times the annualised MTAWE

17c for each $1 24c for each $1 27c for each $1

$36,232 to $72,462

$72,462 is the annualised MTAWE

$6,159 plus 15c for each $1 over $36,231 $8,695 plus 23c for each $1 over $36,231 $9,782 plus 26c for each $1 over $36,231

$72,463 to $108,693

$108,693 is 1.5 times the annualised MTAWE

$11,594 plus 12c for each $1 over $72,462 $17,028 plus 20c for each $1 over $72,462 $19,202 plus 25c for each $1 over $72,462

$108,694 to $144,924

$144,924 is 2 times the annualised MTAWE

$15,942 plus 10c for each $1 over $108,693 $24,274 plus 18c for each $1 over $108,693 $28,260 plus 24c for each $1 over $108,693

$144,925 to $181,155

$181,155 is 2.5 times the annualised MTAWE

$19,565 plus 7c for each $1 over $144,924 $30,796 plus 10c for each $1 over $144,924 $36,955 plus 18c for each $1 over $144,924

Income over $181,155

Costs of children do not increase above this cap

$22,101 $34,419 $43,477

Children aged 13 years and over

Parents' combined child support income 1 child 2 children 3 or more children

$0 to $36,231

$36,231 is 0.5 times the annualised MTAWE

23c for each $1 29c for each $1 32c for each $1

$36,232 to $72,462

$72,462 is the annualised MTAWE

$8,333 plus 22c for each $1 over $36,231 $10,507 plus 28c for each $1 over $36,231 $11,594 plus 31c for each $1 over $36,231

$72,463 to $108,693

$108,693 is 1.5 times the annualised MTAWE

$16,304 plus 12c for each $1 over $72,462 $20,652 plus 25c for each $1 over $72,462 $22,826 plus 30c for each $1 over $72,462

$108,694 to $144,924

$144,924 is 2 times the annualised MTAWE

$20,652 plus 10c for each $1 over $108,693 $29,710 plus 20c for each $1 over $108,693 $33,695 plus 29c for each $1 over $108,693

$144,925 to $181,155

$181,155 is 2.5 times the annualised MTAWE

$24,275 plus 9c for each $1 over $144,924 $36,956 plus 13c for each $1 over $144,924 $44,202 plus 20c for each $1 over $144,924

Income over $181,155

Costs of children do not increase above this cap

$27,536  $41,666 $51,448

Children of mixed age

Parents' combined child support income 1 child 2 children 3 or more children

$0 to $36,231

$36,231 is 0.5 times the annualised MTAWE

N/A 26.5c for each $1 29.5c for each $1

$36,232 to $72,462

$72,462 is the annualised MTAWE

N/A $9,601 plus 25.5c for each $1 over $36,231 $10,688 plus 28.5c for each $1 over $36,231

$72,463 to $108,693

$108,693 is 1.5 times the annualised MTAWE

N/A $18,840 plus 22.5c for each $1 over $72,462 $21,014 plus 27.5c for each $1 over $72,462

$108,694 to $144,924

$144,924 is 2 times the annualised MTAWE

N/A $26,992 plus 19c for each $1 over $108,693 $30,978 plus 26.5c for each $1 over $108,693

$144,925 to $181,155

$181,155 is 2.5 times the annualised MTAWE

N/A $33,876 plus 11.5c for each $1 over $144,924 $40,579 plus 19c for each $1 over $144,924

Income over $181,155

Costs of children do not increase above this cap

N/A $38,043 $47,463

Page last updated: 3 January 2017

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