Child Support Estimator

Step 1 — Child support income

Services Australia starts with each parent's Adjusted Taxable Income (ATI), then deducts the self-support amount ($28,463 in 2024) before calculating obligations.

• Salary, wages, and bonuses
• Business and investment income
• Rental income and dividends
• Certain government payments
• Less: self-support amount deduction
• Less: relevant dependant child amount

Step 2 — Combined costs

The formula uses government research on child-raising costs, adjusted for the number and ages of children and combined parental income.

• 1 child (0–12): 17% of combined income
• 1 child (13+): 23.5% of combined income
• 2 children: 24–29% of combined income
• 3+ children: 27–32% of combined income
• Caps apply at high income levels
• Minimum and maximum amounts apply

Step 3 — Care percentage

The amount of care you provide reduces your liability (if paying) or increases what you receive. Care is measured in nights per year.

• Less than 52 nights: less than regular care
• 52–127 nights (14–34%): regular care
• 128–175 nights (35–47%): substantial care
• 176–182 nights (48–50%): shared care
• 183+ nights: primary care
• Shared care often means no transfer

Step 4 — Final calculation

Your cost percentage is calculated by subtracting your care percentage from your income percentage. The party with a positive cost percentage pays that portion of child costs.

• Income percentage = your CSI / combined CSI
• Cost percentage = income % minus care %
• Positive = you pay; negative = you receive
• Payment = cost % × total child costs
• Monthly = annual ÷ 12
• Fortnightly = annual ÷ 26

How is child support calculated in Australia?

Australian child support is calculated using a formula administered by Services Australia (Child Support). The formula considers both parents' income, the number and ages of children, and the care arrangements. Each parent's Adjusted Taxable Income has a self-support amount deducted, then the combined child support income determines child-raising costs. Your cost percentage (income percentage minus care percentage) determines what you pay or receive.

What income is used for child support calculations?

Child support uses your Adjusted Taxable Income (ATI), which includes taxable income plus any exempt income, reportable fringe benefits, certain tax-free pensions, and net investment losses. This is reduced by the self-support amount ($28,463 in 2024) and any relevant dependant child amounts for children from other relationships. Child Support can also estimate income if tax returns aren't lodged.

How does care percentage affect child support?

Care percentage directly reduces your child support liability. Less than 14% care (52 nights) provides no reduction. Regular care (14–34%) reduces liability by 24%. Substantial care (35–47%) provides a 25% reduction plus additional credit. Shared care (48–50%) means both parents contribute based on their incomes, often resulting in reduced or no transfer between parents.

What is the minimum child support payment in Australia?

The minimum child support assessment is $546 per year for one child (2024 rates), regardless of income or care percentage. This applies when the calculated amount would be less than this minimum. Parents on very low incomes or certain government payments may have the minimum reduced or waived entirely.

Can child support be varied or changed?

Yes. Child support can change through annual income updates, changes in care arrangements, a change-of-assessment application for special circumstances, or by court order. Either parent can apply for a review if circumstances change significantly — for example, job loss, new children, or changed care arrangements.

How is child support different from Family Tax Benefit?

Child support is paid between parents to share the costs of raising children. Family Tax Benefit (FTB) is a government payment to help families with child-raising costs. They're separate but related — receiving child support can affect your FTB amount. FTB Part A is reduced by 50 cents for every dollar of child support received above $1,752 per year.

What happens if a parent doesn't pay child support?

Services Australia (Child Support) can take enforcement action including deducting payments from wages, intercepting tax refunds, placing liens on property, preventing travel overseas, and in serious cases prosecuting for non-payment. They can also issue departure prohibition orders to prevent parents leaving Australia with outstanding debt.

Is child support tax deductible?

No. Child support payments are not tax deductible for the paying parent, and they're not taxable income for the receiving parent. This differs from spousal maintenance (which can be taxable). The child support formula already accounts for after-tax income through the self-support deduction.