When does child support normally end?

On the child's 18th birthday, unless the child is still in secondary school. The default assessment runs to the 18th birthday and then stops. The amount automatically reduces to zero from that date for that specific child; other children in the case continue at their own ages.

What's the secondary school extension?

If a child turns 18 while still in their final year of secondary school (Year 12), child support can be extended to the END of that school year. The receiving parent applies to Services Australia within the school year by submitting evidence of school enrolment. The extension runs to the school's official last day for Year 12 (usually mid-November to mid-December).

Does child support continue for university or TAFE students?

No — Services Australia child support stops at 18 (or end of Year 12 with the school extension). Tertiary study after that isn't covered by child support assessments. Some parents have private agreements continuing financial support during university but those are not enforceable through Services Australia.

What about adult children with disabilities?

Adult children with significant disabilities CAN continue to receive financial support, but not through the standard child support assessment. The receiving parent (or the adult child themselves) may need to apply through different pathways — court orders for continued support, NDIS funding for disability support, Disability Support Pension for the adult child. Each has its own rules.

My ex stopped paying when our oldest turned 18 — was that automatic?

Yes — Services Australia automatically reduces the assessment when a child ages out. The other children's portions don't change, but the share that was for the now-adult child stops. The paying parent doesn't need to "do" anything — it happens via Services Australia's age-out logic. If you have multiple children and the formula amount changed, that's the reason.

Does the child support amount change as children age THROUGH the system?

Yes — the Cost of Children table has different costs for children aged 0-12 vs 13-17. When a child turns 13, the cost-of-children figure for that child jumps to the older bracket. This automatically increases the formula amount. Services Australia re-assesses periodically (annually + on triggers); the next assessment will reflect the new age band.

When does child support end? — age limits, school leavers, and adult dependents

Child support normally ends when the child turns 18 — but there are important exceptions for kids still in secondary school, and the assessment can be extended for adult children with disabilities. Here's exactly when it stops and what to plan for.

Child support stops when the child turns 18 — with one important exception for kids still in their final year of secondary school. This guide walks through the timing, the school-leaver extension, the rules for adult children with disabilities, and the operational mechanics when a child ages out.

For families with multiple children, the assessment automatically adjusts as each child ages out — you don't need to do anything to trigger the reduction, but it pays to understand the timing.

The default — child support ends at 18

The standard rule:

Child support runs from birth to the child's 18th birthday
On the 18th birthday, that child stops generating a child support obligation
Services Australia's systems automatically reduce the assessment from that date
Other children in the case continue at their own ages

If a case has only one child, child support ends entirely on that child's 18th birthday. If there are multiple children, the formula recalculates with the now-adult child removed, and the remaining assessment continues for the younger kids.

The Year 12 extension — keep CS through final school year

The one important exception: kids who turn 18 during their final year of secondary school.

If a child:

Turns 18 during the calendar year they finish Year 12, AND
Is still enrolled in secondary school at that birthday

…the receiving parent can apply for an extension of child support to the end of that school year. The extension runs to the school's official last day for Year 12 students.

How to apply for the extension

Apply through Services Australia (MyGov, phone 131 272, or written request)
Provide evidence of school enrolment for the relevant year
Apply BEFORE the child's 18th birthday where possible — late applications work but create temporary gaps
Services Australia issues a varied assessment running to the school year-end

The school's last day for Year 12 varies by state and school but is typically:

NSW — early to mid-December
VIC — early November (after HSC equivalent)
QLD — mid-November
WA — mid to late November
SA — early to mid-November
TAS — early to mid-December
ACT — early December
NT — early to mid-November

The exact date is the school's official Year 12 finish date. International schools and homeschooled situations follow their specific completion date.

What if the child leaves school before 18?

If a child leaves school before turning 18 (e.g. drops out, transfers to TAFE, starts an apprenticeship), child support still runs to the 18th birthday — the school enrolment isn't required for the default assessment. The Year 12 extension only matters for kids turning 18 while still in school.

What about adult children?

The standard child support system doesn't cover anyone over 18 (or post-Year-12). Adult children with ongoing needs typically rely on different pathways:

Adult children in tertiary study

Services Australia child support stops. Some parents have private financial agreements continuing through university or TAFE, but these are personal arrangements, not enforceable child support.

The adult child themselves may qualify for Youth Allowance or Austudy through Centrelink, which is means-tested on the child's own (and sometimes the parents') income.

Adult children with disabilities

This is where it gets complex. The standard child support assessment ends at 18, but financial support obligations may continue under other frameworks:

Court orders for adult child maintenance, made under the Family Law Act, can require ongoing parental contribution where the adult child has significant disabilities and can't be self-supporting
NDIS provides funded disability support if the adult child meets eligibility — separate from any parental financial contribution
Disability Support Pension (DSP) is income to the adult child, also separate from parental support
Carer Payment / Carer Allowance may be payable to a parent providing care for an adult child with disabilities

These all run separately to the historical child support assessment. The court-order pathway for adult child maintenance requires legal advice — it's narrow and case-specific.

The age-band shift at 13 — costs go up

Before children age OUT at 18, they age UP at 13 from the Cost of Children table's "younger" band to its "older" band. The cost-of-children figure for that child jumps:

Child age	COTC band (rough order of magnitude)
0-12	Lower band — smaller per-child cost
13-17	Higher band — meaningfully larger per-child cost

Services Australia re-assesses periodically. The next assessment after the 13th birthday reflects the new band. For a typical family the amount can step up several thousand dollars per year per child.

This is automatic — neither parent triggers it. But planning for it is worth doing if you're approaching the boundary.

The CS Cost of Children guide covers the table in detail.

Operational changes when CS ends or steps

The month a child turns 18

Services Australia reduces the assessment from the 18th birthday
For Private Collect arrangements, parents should agree on the reduced amount in advance
For Child Support Collect, the deduction notice automatically updates
FTB-A also stops for that child on the 18th birthday (unless they're still in secondary study)

The month a child turns 13

The next periodic re-assessment incorporates the higher cost-of-children figure
Doesn't backdate to the 13th birthday — applies from the next assessment date
Worth checking your notice when re-assessed

When the youngest child finishes school

This is the practical end of child support for the case
Cleanup tasks: close any Child Support Collect arrangement, agree on final payment, document the conclusion
Tax-side effect: receiving parent's ATI for other entitlements (FTB-A no longer involves CS received)

How NestWise helps

Free CS calculator — model the formula with current and projected child ages to see what happens at age boundaries
Full estimator — saves your child ages so the assessment auto-updates as kids age
Your CS picture — track multiple children's ages and projected end dates

Try the free CS calculator →