Get an accurate estimate of your child support payments in under 60 seconds. Built on the official Services Australia 8-step formula.
Your Income
Other Parent's Income
Child support in Australia follows an 8-step formula set by Services Australia. The calculation considers:
Most basic calculators give you a single number. But real child support is more complex:
This calculator handles all of these scenarios. We show you the full breakdown, not just a final number.
The only calculator that handles all 6 Services Australia formulas:
Unlike basic calculators that show a single figure, we explain:
Quick answers to common child support questions
Yes, through a Change of Assessment application if you have special circumstances (10 reasons available). Income changes of 15%+ also trigger automatic reassessment. You must provide evidence to support your application.
Notify Services Australia immediately. If your income drops 15%+, you can request a reassessment. Minimum rates may apply if you receive income support. The new assessment applies from the date you notify them, not retrospectively.
Automatically reviewed annually (July 1) based on tax returns. Can change anytime if income changes 15%+, care arrangements change, or you apply for Change of Assessment. Most parents see changes 1-2 times per year.
Yes. The formula compares both parents' incomes to determine each parent's share. If you don't know the other parent's income, Services Australia can obtain it from the ATO when you apply for an assessment.
Services Australia can access income information from the ATO. You don't need the other parent's cooperation to get an assessment. Simply apply through Services Australia and they'll verify both incomes.
Child support payments depend on both parents' incomes, the number of children, and how much time each parent cares for the children. For example: Parent 1 earns $80,000, Parent 2 earns $50,000, 2 children under 13, Parent 1 has children 30% of nights — Parent 1 would typically pay around $450-500 per month.
If your adjusted taxable income is below the self-support amount ($29,619 for 2025-26), you may pay a minimum annual rate. This is currently $1,815 per year ($151.25 per month) for one child, regardless of care arrangements.
Services Australia reassesses your child support when your income changes by 15% or more from your last tax return. The new assessment applies from the date you notify Services Australia, not retrospectively.
Yes, significantly. When care is exactly 50/50 (182-183 nights each per year), the parent with the higher income pays, but the amount is much lower than in sole-care arrangements.
This is called a multi-case situation. Services Australia applies a Multi-Case Allowance that reduces your child support income to recognise you're supporting children in multiple cases.
If you have a court order or binding child support agreement that sets a specific amount, that overrides the formula. You can still use this calculator to compare what you're paying vs. the formula amount.
No. The formula covers basic living costs only. It does not include private school fees, extracurricular activities, medical costs not covered by Medicare, or childcare fees.
This calculator uses the official Services Australia 8-step formula and is accurate for the scenarios it covers. For a formal assessment, apply through Services Australia.