What counts as adjusted taxable income
Child support isn't based on your salary or your take-home pay — it's based on adjusted taxable income (ATI), which adds several things back on top of your taxable income. If your assessment looks higher than your payslip suggests, this is usually why.
The six components
Your ATI for a child support period is the total of:
| Component | What it captures |
|---|---|
| Taxable income | Your income after deductions, from your tax return |
| Reportable fringe benefits | Salary-packaged cars, loans and other benefits your employer reports |
| Reportable super contributions | Salary-sacrificed and personal deductible super above the compulsory rate |
| Total net investment losses | Negative gearing losses on property and shares are added back |
| Target foreign income | Foreign income not already taxed in Australia |
| Tax-free pensions and benefits | Certain tax-exempt payments, such as some DVA and disability pensions |
The add-backs surprise people
The design intent is to stop income being sheltered from the assessment. Negatively gearing an investment property reduces your taxable income, but the loss is added straight back for child support purposes. The same goes for salary sacrificing into super: it cuts your tax, but not your child support income. Salary packaging through fringe benefits is also captured through the reportable amount on your payment summary.
Which year's income is used
An assessment normally uses your ATI from the last completed financial year before the child support period starts. If your income has dropped substantially since then — by 15% or more — you can apply for the assessment to be based on an estimate of your current income instead, though estimates are later reconciled against your actual tax return and can create a debt if you underestimate.
After ATI: the self-support amount
Whatever your ATI is, the formula first deducts the self-support amount — $31,046 in 2026 — before your income is compared with the other parent's. Only income above that level is treated as available for the costs of the children.
Estimate your child support →This is general information about the published formula, not legal or financial advice. For a formal assessment, contact Services Australia.