Child Support Estimator (Australia)
A free, browser-based calculator. Runs entirely in your browser — no sign up, nothing stored.
Enter Values
How to use this calculator
- Enter both parents' taxable incomes and the current self-support amount.
- Enter your nights of care per year and the Costs of the Children figure (both from Services Australia).
- Press Calculate for a rough estimate of who pays whom and how much.
How it works
This follows the basic Australian (Formula 1) method. Each parent's child support income is their taxable income minus the self-support amount; combined, these give each parent's income percentage.
Your care percentage is converted to a cost percentage using the official Care and Cost table. Your child support percentage is your income percentage minus your cost percentage — if it's positive you pay, if negative you receive. The amount is that percentage of the Costs of the Children.
Worked example
Incomes $100k and $50k, 146 nights' care. Income percentage ≈ 77.8%, cost percentage 35% (40% care), so child support percentage ≈ 42.8%. Against $20,000 costs that's about $8,556 per year.
Tips
- The basic formula here ignores relevant dependent children and multiple child support cases.
- Use your adjusted taxable income, not just your salary.
Frequently asked questions
Is this the official assessment?
No. It's a rough estimate only — just Services Australia can make a formal assessment. Use current figures and get an official assessment before relying on any number.
Where do I find the self-support amount and Costs of the Children?
Both are published by Services Australia and updated each year.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.