Child Support Calculator Australia
Estimate your child support payments using Australia’s official 8-step formula — based on 2026 Services Australia rates.
Calculator
Work Out Your Child Support Amount
👤 Parent A (the paying parent)
Use last year’s taxable income. Include salary, investments, and fringe benefits.
Total nights across all children in this assessment.
👥 Parent B (the receiving parent)
Leave at 0 if the other parent has no income.
Must add up to 365 with Parent A’s nights.
👪 Children
This calculator uses Formula 1 (the standard single-case assessment). If either parent has multiple child support cases, the result is indicative only.
✅ Your Estimate
$0
Estimated Annual Child Support Payable
$0 per month | $0 per fortnight
Paying Parent
—
Receiving Parent
—
Care Level (Payer)
—
Combined Child Support Income
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Cost of Children (Annual)
—
Payer’s Child Support %
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Income & Care Breakdown
SHARE OF COMBINED INCOME
Parent A
0%
Parent B
0%
SHARE OF CARE (NIGHTS)
Parent A
0%
Parent B
0%
Step-by-Step Calculation
Quick Scenarios
Common Situations at a Glance
Click any scenario to pre-fill the calculator above.
Standard split
1 child, 2 nights/wk
Equal share care
50/50, 2 children
High income payer
1 child, low nights
Low income payer
Minimum rate check
Teenagers
2 teens, primary care
Mixed ages
3+ children, mixed
How It Works
The 8-Step Formula Explained
Services Australia uses a standard formula to assess child support. Here’s what happens at each step:
- Child Support Income: Each parent’s taxable income minus the self-support amount ($31,046 in 2026). This is the income available to support the children.
- Combined Income: Both parents’ child support incomes are added together.
- Income Percentage: Each parent’s share of the combined income — for example, 60% / 40%.
- Percentage of Care: Based on the number of nights per year each parent cares for the child.
- Cost Percentage: Determined by the Care and Cost Table. Higher care = higher cost percentage.
- Child Support Percentage: Income % minus Cost %. A positive result means that parent pays; a negative result means they receive.
- Costs of Children (COTC): Looked up from the official table based on combined income, number of children, and ages.
- Annual Amount: Child Support % × COTC = annual amount payable.
Care & Cost Table
Care Percentage and Cost Percentages
The number of nights a parent cares for a child each year determines their “care level” and the proportion of costs they are deemed to meet through that care.
| Care % | Nights/Year | Nights/Fortnight | Care Level | Cost % |
|---|---|---|---|---|
| 0–13% | 0–51 | 0–1 | Less than regular care | 0% |
| 14–34% | 52–127 | 2–4 | Regular care | 24% |
| 35–47% | 128–175 | 5–6 | Shared care | 25% + 2% per % above 35% |
| 48–52% | 176–189 | 7 | Shared care (equal) | 50% |
| 53–65% | 190–237 | 8–9 | Shared care | 51% + 2% per % above 53% |
| 66–86% | 238–313 | 10–12 | Primary care | 76% |
| 87–100% | 314–365 | 13–14 | More than primary care | 100% |
Costs of Children
Costs of Children Table — 2026 Rates
The table below shows annual costs used in the formula. These represent net costs after Family Tax Benefit is taken into account.
Children aged 12 and under
| Combined CS Income | 1 child | 2 children | 3+ children |
|---|---|---|---|
| $0–$46,569 | 17c per $1 | 24c per $1 | 27c per $1 |
| $46,570–$93,137 | $7,917 + 15c per $1 over $46,569 | $11,177 + 23c per $1 over $46,569 | $12,574 + 26c per $1 over $46,569 |
| $93,138–$139,706 | $14,324 + 12c per $1 over $93,137 | $21,888 + 20c per $1 over $93,137 | $24,682 + 25c per $1 over $93,137 |
| $139,707–$186,274 | $20,490 + 10c per $1 over $139,706 | $31,202 + 18c per $1 over $139,706 | $36,324 + 24c per $1 over $139,706 |
| $186,275–$232,843 | $25,147 + 7c per $1 over $186,274 | $39,584 + 10c per $1 over $186,274 | $47,500 + 18c per $1 over $186,274 |
| Over $232,843 (cap) | $28,407 | $44,241 | $55,882 |
Children aged 13 or older
| Combined CS Income | 1 child | 2 children | 3+ children |
|---|---|---|---|
| $0–$46,569 | 23c per $1 | 29c per $1 | 32c per $1 |
| $46,570–$93,137 | $10,711 + 22c per $1 over $46,569 | $13,505 + 28c per $1 over $46,569 | $14,902 + 31c per $1 over $46,569 |
| $93,138–$139,706 | $20,956 + 12c per $1 over $93,137 | $26,544 + 25c per $1 over $93,137 | $29,338 + 30c per $1 over $93,137 |
| $139,707–$186,274 | $26,544 + 10c per $1 over $139,706 | $38,186 + 20c per $1 over $139,706 | $43,309 + 29c per $1 over $139,706 |
| $186,275–$232,843 | $31,201 + 9c per $1 over $186,274 | $47,500 + 13c per $1 over $186,274 | $56,814 + 20c per $1 over $186,274 |
| Over $232,843 (cap) | $35,392 | $53,544 | $66,128 |
Mixed ages (2 children)
| Combined CS Income | 2 children (mixed) | 3+ children (mixed) |
|---|---|---|
| $0–$46,569 | 26.5c per $1 | 29.5c per $1 |
| $46,570–$93,137 | $12,341 + 25.5c per $1 over $46,569 | $13,738 + 28.5c per $1 over $46,569 |
| $93,138–$139,706 | $24,216 + 22.5c per $1 over $93,137 | $27,010 + 27.5c per $1 over $93,137 |
| $139,707–$186,274 | $34,694 + 19c per $1 over $139,706 | $39,816 + 26.5c per $1 over $139,706 |
| $186,275–$232,843 | $43,542 + 11.5c per $1 over $186,274 | $52,157 + 19c per $1 over $186,274 |
| Over $232,843 (cap) | $48,897 | $61,005 |
Key Factors
What Affects Your Child Support Assessment
Includes your taxable income plus reportable fringe benefits, total net investment losses, reportable employer super contributions, and certain foreign income. It can differ significantly from your PAYG income alone.
Measured by the number of nights per year the child stays with each parent. Even small differences can shift a parent between care categories, which dramatically changes the cost percentage — and therefore the payment amount.
Older children (13+) cost more under the table. If you have children of different ages, a blended “mixed ages” table is used. Costs are reassessed when children turn 13.
If a parent is legally responsible for other children (e.g., from a new relationship), a relevant dependant child allowance is deducted from their taxable income before calculating child support income, reducing their obligation.
In 2026, the self-support amount is $31,046. This is deducted from each parent’s adjusted taxable income before calculations begin — it reflects the income a parent needs just to support themselves.
If your assessment falls below $551/year, the minimum rate applies. If your income is deliberately low and you have less than 35% care, the fixed rate of $1,825 per child per year may apply instead.
Changing Your Assessment
Ways to Change a Child Support Assessment
A Services Australia assessment can be changed in several ways. Each has different requirements and legal implications.
| Method | How It Works | Who Can Apply |
|---|---|---|
| Change of Assessment | Apply to Services Australia if your circumstances aren’t reflected in the formula (e.g., high necessary expenses, medical costs) | Either parent |
| Income Estimate | If your income has dropped, you can ask Services Australia to use an estimated income rather than last year’s figure | Paying parent |
| Limited Child Support Agreement | A written agreement signed by both parents setting a different amount — must be at least 75% of the formula amount | Both parents |
| Binding Child Support Agreement | A formal agreement with independent legal advice for each parent. Can set any amount — including $0. | Both parents |
| Court Order | A court can set child support outside the formula in complex cases | Either parent via court |
Payment Options
Private Collect vs Child Support Collect
Once an assessment is made, parents can choose how payments are made.
| Feature | Private Collect | Child Support Collect |
|---|---|---|
| Who manages payments? | Parents arrange directly | Services Australia collects and pays out |
| Flexibility | High — any agreed method | Lower — set schedule |
| Enforcement available? | Only if you switch to CS Collect | Yes — debt recovery, tax intercept, garnishing wages |
| FTB implications | May affect Family Tax Benefit Part A | Receiving parent gets full FTB Part A entitlement |
| Best for | Co-operative relationships | Where payments are unreliable or withheld |
FAQ
Frequently Asked Questions
How often is child support reassessed?
Child support is automatically reassessed each year when the Australian Taxation Office provides updated income data. Either parent can also request a reassessment if their circumstances change significantly — such as a job loss, major income increase, or a change in care arrangements.
What is “adjusted taxable income” and what does it include?
Adjusted taxable income (ATI) starts with your taxable income and adds reportable fringe benefits, reportable employer super contributions, total net investment losses, and certain tax-exempt foreign income. It gives a more complete picture of a parent’s financial capacity than taxable income alone.
Does 50/50 care mean no child support is paid?
Not necessarily. With exactly 50/50 care, both parents have a cost percentage of 50%. If their incomes differ, the higher-earning parent will still have a positive child support percentage and may owe payments to the lower-earning parent.
Can child support be reduced if I pay school fees or other expenses directly?
Possibly. If you pay for non-agency-assessed expenses (like school fees, medical costs, or extracurriculars) and the receiving parent agrees, these can be included in a child support agreement as non-cash contributions. Without an agreement, they do not reduce the assessed amount.
What happens if a parent refuses to provide their income?
If a parent fails to provide income details, Services Australia can use a deemed income based on the average weekly earnings benchmark — currently 2/3 of male average weekly earnings. This is often higher than actual income, so it is usually in a parent’s interest to declare their income.
Is child support taxable or tax-deductible?
No. Child support payments are not taxable income for the receiving parent and are not tax-deductible for the paying parent. They have no direct impact on either parent’s tax return.
When does child support end?
Child support generally ends when the child turns 18, or when the child completes secondary school — whichever comes later. It can end earlier if the child marries, enters a de facto relationship, or is legally adopted. Court orders for adult child maintenance (under the Family Law Act) may extend beyond 18 in some cases.
What if my ex-partner takes the children overseas?
Australia has reciprocal child support enforcement arrangements with many countries, including the UK, New Zealand, and the USA. If a paying parent moves overseas, Services Australia may still be able to collect payments through the relevant overseas authority. If a child is taken overseas without consent, this may constitute international parental abduction and you should seek legal advice immediately.
Worked Example
Step-by-Step Worked Example
Scenario: Sarah earns $90,000/year and cares for 2 children (both aged under 13) for 292 nights per year. James earns $60,000/year and cares for the same children 73 nights per year. Neither parent has other dependants.
- Child support income: Sarah = $90,000 − $31,046 = $58,954. James = $60,000 − $31,046 = $28,954.
- Combined income: $58,954 + $28,954 = $87,908
- Income percentage: Sarah = 58,954 / 87,908 = 67.0%. James = 32,954 / 87,908 = 33.0%.
- Percentage of care: Sarah = 292/365 = 80%. James = 73/365 = 20%.
- Cost percentage: Sarah at 80% care = primary care = 76%. James at 20% care = regular care = 24%.
- Child support percentage: Sarah = 67.0% − 76% = −9.0% (receives). James = 33.0% − 24% = +9.0% (pays).
- COTC (2 children under 13, combined income $87,908): $11,177 + 23c × ($87,908 − $46,569) = $11,177 + $9,508 = $20,685
- Annual child support: 9.0% × $20,685 = $1,862/year (James pays Sarah ~$155/month)
References
References
- Services Australia. (2026). Basic child support formula. Australian Government. https://www.servicesaustralia.gov.au/basic-child-support-formula
- Services Australia. (2026). Fixed and minimum child support assessments. Australian Government. https://www.servicesaustralia.gov.au/fixed-and-minimum-child-support-assessments
- Department of Social Services. (2025). 2.2.2 Formula 1 — the basic formula: a single case assessment. Child Support Guide. Australian Government. https://guides.dss.gov.au/child-support-guide/2/2/2
- Department of Social Services. (2025). 2.3.1.20 Current COTC Tables. Child Support Guide. Australian Government. https://guides.dss.gov.au/child-support-guide/2/3/1/20
- Department of Social Services. (2025). 2.3.4 Minimum annual rate. Child Support Guide. Australian Government. https://guides.dss.gov.au/child-support-guide/2/3/4
- Department of Social Services. (2025). 2.3.5 Fixed annual rate. Child Support Guide. Australian Government. https://guides.dss.gov.au/child-support-guide/2/3/5
- Law Society of South Australia. (2026). Child support assessments. Law Handbook. https://www.lawhandbook.sa.gov.au/ch07s01s05.php
- Child Support (Assessment) Act 1989 (Cth), Part 5 — Assessment of child support.
- Child Support (Assessment) (Minimum and Fixed Annual Rates) Notice 2025 (Cth).