How is child support calculated in Australia in 2026?

Services Australia uses an 8-step formula. Each parent's adjusted taxable income has a self-support amount of $31,046 (2026) deducted, plus an allowance for other dependent children. The incomes are combined and each parent's income percentage is compared with their cost percentage (based on nights of care). The positive difference is multiplied by the costs of the children from the 2026 Costs of the Children table, which caps combined income at $232,843 (2.5 times annualised MTAWE of $93,137). Source: Services Australia basic child support formula, checked 20 July 2026.

What is the minimum child support payment in 2026?

The minimum annual rate for child support periods starting in 2026 is $551 per year per case. It applies when the formula works out to less than $551 and the paying parent has less than regular care (under 14% of nights). Low-income parents who did not receive income support in the last relevant year and have less than shared care may instead pay the fixed annual rate of $1,825 per child per year, capped at 3 children. Source: Services Australia fixed and minimum assessments, checked 20 July 2026.

What happens if I underestimate my income for child support?

Income estimates are reconciled against your actual adjusted taxable income after you lodge your tax return. If you underestimated, the shortfall becomes a child support debt and a penalty can be added. The risk is one-way: if you overestimated and paid too much, the excess is not automatically refunded. Update your estimate with Services Australia as soon as your income changes.

Can a child support assessment be changed if the formula result is unfair?

Yes. Either parent can apply to Services Australia for a change of assessment in special circumstances under one of 10 legislated reasons — including high costs of spending time with the child, a child's special needs, the income, property or financial resources of a parent not being reflected in the assessment, or prior property settlements. Care or income changes are handled separately by updating your details.

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Estimate your child support using the official Services Australia 8-step formula with 2026 rates. Enter both parents' incomes, the children's ages and nights of care to see who pays and how much.

Last verified: 20 July 2026Jump to calculator ↓

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