Child Support Calculator Australia (Easy Questions)

Understanding Your Result

The estimate is calculated using the legislated Australian child support formula. The calculator uses the same calculation applied by Services Australia.

You can adjust the inputs and immediately see how the assessment changes. That allows you to easily test how income and care levels affect child support.

The calculator is accurate. For details of accuracy testing, see verification.

How the Calculation Works

The calculator follows the Australian Government’s 8-step child support formula. The formula compares each parent’s financial capacity with the level of care they provide.

Income
The self-support amount ($31,046 for 2026) is deducted from each parent’s taxable income. The remaining incomes are combined, and each parent’s percentage share of the total is calculated.

Care
Nights per fortnight are converted into an annual care percentage. A legislated cost table then assigns a care credit (for example, 14%–34% care equals a 24% cost credit). The care credit is offset against the income share to determine each parent’s position.

Assessment
The government cost table estimates the cost of raising the children based on the combined income. That cost is multiplied by the net position.
• Positive result: you pay child support
• Negative result: you receive child support

Using the Calculator

The sections below explain each input and how it affects the result.

Your taxable income
Enter your annual taxable income. Services Australia usually uses the most recent tax return unless an income estimate is provided. Salary-sacrificed superannuation is added back for child support purposes, so reducing taxable income through super contributions does not reduce child support long-term.

Other parent’s income
Enter the other parent’s annual taxable income. The most recent recorded income is normally used, but updated estimates may later be applied and reassessed retrospectively.

Children’s ages
Enter the number of children aged 0–12 and 13–17. Teenagers attract higher cost assumptions under the government cost table. Child support normally continues until age 18 and may extend to the end of Year 12 in some cases.

Your care (nights per fortnight)
Enter the number of overnight stays in a typical fortnight. Care is calculated as a percentage derived from the 14-night cycle. For example, 50% care equals 7 nights per fortnight.

Interpreting the Result

The calculator shows the annual assessment and the equivalent monthly amount. Services Australia assesses annually but payments are usually made monthly.

The parent with greater care commonly receives child support, but a higher-income parent may still pay even with majority care.

Low income rule (2026)
In low-income cases the legislation normally applies a fixed annual amount ($1,825 per year, per child). This calculator applies that fixed amount where the statutory conditions are met.

The legislation also contains a lower “minimum rate” ($551 per year). That rate applies only in uncommon situations where a parent with very low income is not receiving income support and successfully applies for an exemption, so it is not included in this calculation.

With shared care (128 nights or more per year), child support can fall below the fixed amount, including to $0, because the normal formula continues to operate using both parents’ incomes and care levels. Amounts are indexed and usually change slightly each year.

Accuracy

The calculator has been compared with the Services Australia estimator and other widely used calculators. Testing confirms that the calculator above produces the same results as Services Australia, while the other calculators we tested all failed by some margin.

See the full comparison.

Related tools

If care varies across the year, use the Care Percentage Calculator to convert schedules into a care percentage.

Housing affordability is often the next constraint after child support. This rent affordability calculator can help sense-check weekly rent after tax.

About

This calculator is maintained by Child Support Australia. Background information about the project and author is available on the about page.