Employment & leave Australia
Child Support Calculator Australia
Child support in Australia is worked out by a formula that compares each parent's income and the time each spends caring for the children. This calculator follows the Services Australia basic eight-step formula, using the 2026 self-support amount and the costs of children table, to estimate what one parent pays the other.
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Before tax, including reportable super and fringe benefits.
Parent B has the remaining nights.
Child support to pay
—Paid by
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Per fortnight
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Per week
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Per month
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Costs of the children (the shared total)
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Child support percentage of the paying parent
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The eight steps
Working with a different rate? Edit the rates this calculator uses
These are the figures we verified on 2026-10-26. Change them to work with a historic period, or with a new rate that has been announced but which we have not published yet.
Services Australia; one third of MTAWE for child support periods starting in 2026
Services Australia, 2026
Services Australia, 2026
An estimate, not an assessment. An estimate of the basic formula for one case with the same care arrangement for every child. Services Australia decides your actual assessment using your tax records, and special circumstances, other children, minimum and fixed rates, change of assessment and agreements can all alter the result. This is general information and not legal advice.
How is child support calculated in Australia?
Services Australia subtracts a self-support amount of $31,046 from each parent's income, shares the costs of the children by income, and then offsets each parent's share of care. With parent A on $90,000, parent B on $50,000, two children under 13 and A having 2 nights a fortnight, A pays about $9,500 a year, or $365 a fortnight.
Income and care
Child support income starts with adjusted taxable income, which is your taxable income plus reportable fringe benefits, reportable super and some other items. A self-support amount is taken off for each parent, because the formula assumes a parent needs some income to support themselves before contributing. The more time a parent spends with the children, the more of the costs they are treated as meeting directly, which reduces the amount they pay.
Other things that can change the result
Services Australia can vary an assessment for special circumstances, such as high costs of a child's disability, or a parent supporting other children. Parents can also agree on a different arrangement through a child support agreement. If a parent has no income or little income, a minimum annual rate of $551, or a fixed rate of $1,825 per child where the paying parent has little care, may apply.
To see your income after tax, use the take-home pay calculator.
How this is calculated
The rule, step by step, so you can check any figure by hand.
child support income = adjusted taxable income − self-support amount ($31,046), not below nilincome percentage = each parent's share of the combined child support incomecare percentage = nights ÷ 14, rounded to a whole percent; cost percentage from the care and cost table (14% to 34% care is 24%, 35% to 47% is 25% plus 2% per point over 35, 48% to 52% is 50%, 53% to 65% is 51% plus 2% per point over 53, 66% to 86% is 76%, 87% or more is 100%)child support percentage = income percentage − cost percentage; only a positive percentage payscosts of children from the table for the number and ages of the children and the combined income, capped above $232,843child support = the paying parent's percentage × the costs of the children
Steps 1 to 3 give each parent's share of the pot of income available after they have supported themselves. Steps 4 and 5 turn the time each parent has the children into a share of the costs they meet directly. Step 6 compares the two: a parent whose income share is bigger than the share of costs they meet through care pays the difference, as a percentage of the costs of the children from the table.
The costs of children are not what you spend: they are an amount set by the table from the parents' combined income, the number of children and their ages, net of Family Tax Benefit. They rise with income but stop rising above $232,843, so very high earners pay a capped amount. Care is counted in nights; the official formula uses actual nights over a year, so this estimate can differ by a point or two.
A worked example
Parent A earns $90,000, parent B $50,000, two children aged 12 or under, A has 2 nights a fortnight.
- Child support incomes$58,954 and $18,954
- Costs of the children$18,385
- Income share of A75.7%
- Cost share of A through care24%
- A pays$9,500 a year, $365 a fortnight
A pays about $9,500 a year.
Services Australia's own estimator uses your exact tax details.
Getting an official assessment
Services Australia works out your child support assessment when you apply, using information from the Australian Taxation Office. You can use their child support estimator, which asks for more details than this tool, and you can ask for a review or change of assessment if you think the result is not right.
What it leaves out
Multiple cases, different care for different children, relevant dependent children and shared household circumstances are not modelled. The same care percentage is assumed for each child, which is the usual case.
What this calculator does not do
- One case, same care for every child
- 2026 formula values
- Minimum and fixed rates not applied
- An estimate, not legal advice
Common questions
How is child support calculated?
With an eight-step formula that compares each parent's income and share of care.
What is the self-support amount?
$31,046 for 2026, taken off each parent's income before the shares are worked out.
Does shared care reduce child support?
Yes. More nights of care means a higher cost percentage and a lower amount to pay.
Is the result what I will pay?
No. Services Australia decides the assessment.
Where can I get help?
From Services Australia, which offers a free estimator and support for parents.
Where these numbers come from
- Services Australia — basic child support formula The eight steps, the care and cost table and the costs of children tables
- Child Support Guide — current COTC tables The 2026 costs of children table
- Child Support Guide — current formula values The 2026 self-support amount, minimum and fixed rates
Rates last verified 2026-10-26 Every figure Services Australia sets is re-checked against the source at least once a year, and again whenever a change is announced. Out of date? Tell us and we will fix it.
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