Reading your child support assessment notice — what each line means

Your child support assessment notice is the document that decides what changes hands between you and your ex for the next 12 months. It looks plain — a single page of figures and tables — but each line is a lever. The income figures determine the headline number. The care percentages determine how the formula applies. The direction tells you who pays whom. And tucked at the bottom: the 28-day window to object before the assessment locks in.

This guide walks through what each line means and what to verify before the window closes.

The header — who, when, and for what period

The top of the notice always shows:

• Case number — your unique Services Australia CS case ID. Keep this; it's the reference number for any future call, objection, or change of assessment.
• Date of notice — the day Services Australia issued it. The 28-day objection clock starts ticking from this date (not the day you received it).
• Child support period — the 12-month window the assessment applies to. Periods usually begin on the anniversary of your original assessment date, so if you first registered in March, your periods run March–March.
• Children in the case — every child being assessed, with their date of birth. If a child is missing, that's a major issue — call before doing anything else.

The income block — each parent's assessed ATI

For each parent the notice shows:

• Adjusted Taxable Income (ATI) — the figure used in the formula. Almost always from your most recent ATO assessment, unless you've supplied a current-year estimate or had a Change of Assessment ruling.
• Income year — the FY the ATI relates to (e.g. "FY 2024-25"). Both parents should be on the same FY where possible; mismatched FYs are a red flag and worth calling about.
• Self-support amount — the deduction applied before calculating child support. Both parents get this — it's one-third of male total average weekly earnings (MTAWE), around $30,000 in 2025-26.
• Child support income — your ATI minus the self-support amount minus any "other-children" adjustment. This is the figure the formula actually uses.

What to verify:

1. Does your ATI match your tax return for the stated FY (or your supplied estimate)?
2. Does your ex's ATI look plausible? If it's dropped sharply and you have reason to think they're earning more (cash, business, capacity), that's a possible Change of Assessment (Reason 8).
3. Is the FY the most recent available? If you've lodged your latest tax return but the notice still uses the older year, raise it — they may not have synced.

The care block — who has the kids how often

For each parent, for each child, the notice shows:

• Care percentage — Services Australia's recorded percentage of nights the child spends with you. Translates from nights-per-fortnight as follows:

The 35% threshold is where the formula changes its treatment — if you cross into shared care territory, both parents' care costs are netted against the formula, often producing a different headline number. If your actual care has shifted past 35% but the notice still shows you below, that's worth flagging immediately.

What to verify:

1. Does the percentage match the actual nights-per-fortnight in the past 12 months? Annual average, not just the last month.
2. Has anything changed recently (school start, schedule shift, child moved between homes)?
3. If you're near a bracket boundary (e.g. 34% vs 35%), tiny differences in counting can flip the formula. Call to clarify if you're close.

The cost-of-children block

The notice references the Cost of Children Table for each child's age band:

• 0–12 — uses the "younger child" cost factors
• 13–17 — uses the "older child" cost factors (higher)
• The table itself is indexed annually around January 1

It then calculates the total cost of children the case is assessing — the sum across all children, scaled by each parent's combined child support income.

What to verify: that the age bands are right — kids switching from 12 → 13 mid-period can trigger a recalculation worth noticing.

The result block — direction, amount, method

The bottom of the notice is the consequential bit:

• Annual payable amount — what changes hands across the 12 months.
• Direction — "[Parent A] pays [Parent B] $X per year". The direction is determined by which parent has the higher excess income share above their share of care costs. Switching direction is possible if incomes or care change materially.
• Periodic amount — the per-fortnight or per-month equivalent (the figure that's actually collected).
• Collection method — Services Australia ("Child Support Collect") or Private collect (parents transfer directly; CSA stays informed but doesn't pursue payments).

What to verify:

1. Does the direction make sense given the incomes and care percentages?
2. Is the periodic amount affordable as a paying parent? If not, that's an early signal you may need to act — late payments accrue penalty interest.
3. Is the collection method what you expected? Switching from CS collect to private collect needs both parents to agree; the reverse can be requested unilaterally by either parent if private collect is failing.

The objection window — 28 days

At the bottom of the notice, in smaller print, you'll see something like:

"If you disagree with this decision, you can lodge an objection within 28 days. To object, contact Services Australia on 131 272 or use your myGov account."

This 28-day window is for factual errors — wrong income figure, wrong care percentage, wrong FY, wrong children. It's not the right tool for "the formula produced an unfair result" — that's what Change of Assessment is for, and that has its own (longer) timeline.

If you object within 28 days, the assessment continues at the existing amount while Services Australia reviews. They have 60 days to decide. If they confirm the assessment, you can take it to the Administrative Appeals Tribunal within 28 days of that confirmation.

The audit habit

The best discipline is to read every notice the day it arrives, verify the four key facts (your income, ex's income, care percentages, payable amount), and decide on action within the 28-day window. Once the window closes you've effectively accepted the assessment until something else changes.

How NestWise helps

The CS Assessment Scanner (scan a notice) does the audit for you:

• Takes a photo or PDF of your assessment notice
• Extracts each parent's assessed ATI, care percentages, payable amount, direction, and date
• Compares to your profile — if your profile says your ATI is $95,000 but the notice says $87,000, we flag the drift
• Compares to last notice — if your ex's ATI dropped 20% year-on-year, we flag it as a potential Change of Assessment ground

Importantly: the uploaded file is not stored. The image or PDF is processed in memory, the structured fields are returned, and the buffer is discarded at the end of the request. Only the extracted fields (numbers, dates) are saved if you choose to save the assessment to your profile.

Try the CS Assessment Scanner →

Related guides

• Change of Assessment — the 10 grounds for varying child support
• Non-Agency Payments — how to credit direct spending against CS
• Child Support Formula explained
• Shared Care impacts on child support

Sources: Services Australia — Understanding your child support assessment, Child Support Guide §2.4 (DSS), Child Support (Assessment) Act 1989.