Australia Child Support Estimator 2026
Estimate child support using the Services Australia 8-step formula — both parents' income, care percentage, the Costs of Children Table, and the self-support amount ($31,046).
By Sammy S. · Founder · AuthorUpdated for 2026
Estimates only — not legal advice. Services Australia makes final determinations. Consult a family law lawyer.
Child Support Calculator
Enter details to estimate payments
8-step formula based on both parents' income, care %, and the Costs of Children Table.
Parent A's custody %. Parent B calculated automatically.
Australia · 8-Step Formula
Estimated Child Support
Weekly
$11
Biweekly
$21
Monthly
$46
Annual
$551
Income & custody split
Calculation breakdown
Guideline: Child Support (Assessment) Act 1989
Updated: 2026 · Official source
Minimum annual rate of $551 applied.
Recalculate if income changes by about 15–20% or more.
Shared custody can lower the paying parent's obligation.
This is an estimate only — courts make the final order.
Child support is generally not tax deductible or taxable income.
Add-ons like childcare, insurance, or medical costs can raise the total.
High-income cases above guideline caps often use court discretion.
Verify amounts with the official calculator for your location.
Consider a family law professional before relying on any estimate.
Estimate only — not a court order.
Key values — 2026
- Self-support amount$31,0461/3 of MTAWE — deducted from each parent's ATI
- Annualised MTAWE$93,137
- Income cap (2.5 × MTAWE)$232,843
- Equal care threshold48–52% care = 50% cost %
- Minimum care for cost impact14% (≈51 nights/year)
Care % → Cost %
Other countries
Related tools
The 8-step formula — what makes Australia's approach different
Australia's child support system is more mathematically complex than most other countries' approaches, and for good reason — it attempts to account for both parents' incomes and the actual time each parent spends with the child. Other systems (like the UK's) only use the paying parent's income. Australia's formula says: both parents have financial responsibility, and both parents' care time is counted economically.
The self-support amount ($31,046) is deducted from both parents' adjusted taxable income first. This is policy design: it acknowledges that each parent needs a base amount to maintain themselves before contributing to child costs. Only the income above that threshold is "child support income." The self-support amount equals one-third of the annualised Male Total Average Weekly Earnings (MTAWE) and is indexed each financial year.
The care percentage trap — why 14% is the key threshold
The most misunderstood aspect of Australia's formula is the care-to-cost conversion. A parent with less than 14% care has a 0% cost percentage — meaning from the formula's perspective, they bear no direct costs for the child. This typically translates to maximum child support liability for that parent. 14% care equals approximately 51 nights per year — just under one night per week.
The jump from 0% to 24% cost percentage at 14% care is a significant economic cliff. Moving from 50 nights/year to 52 nights can meaningfully reduce the payment. Courts and Services Australia look at the actual care arrangements, including daytime care — but for the formula, nights are the primary measure.
Example (2026 values): Parent A earns $90,000/yr ATI, Parent B earns $45,000/yr ATI. Parent B has 70% care. Self-support deducted: each parent's CSI = ATI − $31,046. Combined CSI = $58,954 + $13,954 = $72,908. Income %: Parent A 80.9%, Parent B 19.1%. Care → Cost: 70% care → 76% cost for B; 30% care → 24% cost for A. Child support % for A: 80.9% − 24% = 56.9%, so Parent A pays.
Costs of Children Table — how age and income affect the amounts
The Costs of Children Table represents what research estimates families actually spend on children at different income levels. Crucially, the percentages decline as combined income increases — this is the "economies of scale" effect. A family earning twice as much doesn't spend twice as much on children. The table also distinguishes between younger children (0–12) and teenagers (13+), since teenage costs are higher.
| Children | 0–½ MTAWE | ½–1 MTAWE | 1–1.5 MTAWE | 1.5–2 MTAWE | 2–2.5 MTAWE |
|---|---|---|---|---|---|
| Children aged 0–12 years | |||||
| 1 child | 17% | 15% | 12% | 10% | 7% |
| 2 children | 24% | 23% | 20% | 18% | 10% |
| 3+ children | 27% | 26% | 25% | 24% | 18% |
| Children aged 13+ years | |||||
| 1 child | 23% | 22% | 12% | 10% | 9% |
| 2 children | 29% | 28% | 25% | 20% | 13% |
| 3+ children | 32% | 31% | 30% | 29% | 20% |
MTAWE = $93,137 annualised (2026). Percentages applied progressively to combined child support income. Source: DSS Child Support Guide 2.4.6.