A separated family's care percentage doesn't just sit in the child support formula. The same percentage — based on the actual nights (or pattern) the child spends with each parent — cascades through Child Care Subsidy, Family Tax Benefit Part A, Rent Assistance (because RA loads on FTB-A), and even into FTB Part B in some cases. Four different systems, one underlying care number, four different ways of applying it. Get the percentage right and they all reconcile cleanly; get it wrong (or report it differently to different agencies) and you'll see drift in multiple places at once.
This guide walks through how each system uses the care percentage — what gets apportioned, what stays whole, where the surprises are. Every figure here is what our Child Support Estimator and FTB calculator use, verified against Services Australia and the DSS Family Assistance Guide §2.1.1.25.
The one care percentage, four different systems
| System | What it does with the care % |
|---|---|
| Child Support | Maps the % to a 5-band cost-percentage table (24% / 25–49% / 50% / 51–75% / 76%) and uses it in the formula's "cost share" step. |
| FTB Part A | Care % maps to a share through a stepped scale, not one-for-one. 50/50 → each parent gets 50%. Below 35% care → no FTB-A for that child. |
| FTB Part B | Same apportionment as Part A for the youngest-child age calculation; primary/secondary earner test still applies to each household separately. |
| CCS | Per-enrolment, not per-child. Each parent claims CCS for the days the child is in care UNDER THEIR ENROLMENT. Total cap remains the standard CCS cap. |
| Rent Assistance | Paid as part of FTB-A; uses the same care % for apportionment. Counts shared-care kids fractionally for the "number of children" bracket. |
| Newborn Supplement | Apportioned with the FTB-A entitlement that it loads onto — so a 50/50 shared-care newborn means each parent gets ~50% of the supplement. |
The fact that the same care % drives all of this is good and bad. Good because the number itself is stable across systems. Bad because each agency manages its own claim separately, and small drift in how you report it can produce mismatched entitlements — your ex's FTB might be calculated at 35% care while your CCS provider has you down for 40%, and Services Australia has to reconcile that at EOFY.
Try the free CS calculator → · Open the full estimator → Pop in both incomes + care % + number of kids and we'll show every step of the formula working.
Child Support — the 5-band cost percentage
Services Australia uses 5 care-percentage bands. Each maps to a "cost percentage" — the share of the children's cost that parent is treated as already meeting through their care.
| Care band | Care % | Cost percentage |
|---|---|---|
| Below regular care | 0–13% | 0% |
| Regular care | 14–34% | 24% |
| Shared care (lower) | 35–47% | 25–49% (sliding) |
| Equal care | 48–52% | 50% |
| Shared care (upper) | 53–65% | 51–75% (sliding) |
| Primary care | 66–86% | 76% |
| Above primary | 87–100% | 100% |
The formula then uses this cost percentage alongside each parent's income to calculate the transfer. Even with equal 50/50 care, a higher-earning parent typically still pays because the income test runs separately — only when both incomes AND both care percentages are roughly equal does the payment land near zero. See our shared-care child support guide for the worked examples.
FTB Part A — a stepped scale, not a straight line
FTB-A also converts your care percentage into a share, but the conversion is NOT one-for-one. This is the part most people get wrong, because "50/50 care means half the payment" happens to be true and makes the rest look linear.
| Your care percentage | Share of that child's FTB-A |
|---|---|
| Below 35% | Nothing — not an FTB child for you |
| 35% to 47% | 25%, rising two points for every point of care above 35 |
| 48% to 52% | A flat 50% |
| 53% to 65% | 51%, rising two points for every point of care above 53 |
| Above 65% | 100% — treated as the primary carer |
So 35% care gives a quarter of the payment, not a third. 30% care gives nothing at all. And the two parents' shares do not add up to 100% at every split — at 40/60 one gets 35% and the other 65%.
Below 35% you may still be a "regular care" carer if you have at least 14% care. That does not pay FTB-A, but it does keep you eligible for Child Care Subsidy for that child and can support a health care card. The 14% figure is real; it is just not the FTB-A threshold.
Care percentage itself is nights divided by 14, rounded DOWN below 50% and UP at 50% or above.
Worked example:
- Two parents, one child aged 6, 50/50 care.
- Family ATI for Parent A: $70,000. Family ATI for Parent B: $50,000.
- Parent A's maximum FTB-A for that child at 100% care: $235.48/fortnight, plus the end-of-year supplement.
- At 50% care the share is half, so the starting point is $235.48 ÷ 2 — then Parent A's own income test runs on top of that, which can reduce it further.
- Parent B's FTB-A is calculated against Parent B's own family ATI (which may include a new partner's income), apportioned to 50%.
- The two halves are NOT required to add up to anything in particular — they're independent claims against each parent's separate household income.
Run the NestWise FTB Calculator → Tell us your situation including the shared-care percentage and we'll show your exact FTB-A and FTB-B.
FTB Part B — uses youngest-child age × apportioned
FTB-B is paid per FAMILY (not per child), using the YOUNGEST eligible child's age to set the rate. For a shared-care family:
- The youngest-child age applies to whoever the child is currently with (so each parent uses their applicable rate based on shared-care youngest).
- The income test (primary earner cap of $124,327 + secondary earner taper) runs against each household separately.
- The result is apportioned by the FTB-A care percentage.
So a single parent with a shared 50/50 newborn might get half the under-5 FTB-B rate, against their own income test only.
CCS — per enrolment, not per child
CCS is where shared care works differently. CCS isn't apportioned — each parent claims CCS independently for the days the child is in approved care UNDER THEIR ENROLMENT.
- Both parents must have separate CCS enrolments for the child if both want to claim. The provider sets these up.
- Each parent's CCS rate is calculated against their OWN family income (their household ATI, including any new partner).
- The 5% withholding + EOFY reconciliation happen per-parent.
- Total subsidised hours across both enrolments: still capped at the standard CCS cap (72 hrs/fortnight under the 3 Day Guarantee or 100 hrs if both parents in that household meet the activity test for the higher tier).
Practical implication: your CCS rate as a shared-care parent depends on YOUR household income — not the other parent's. A high-earning ex doesn't pull your CCS rate down.
Rent Assistance — rides on FTB-A's apportionment
Because RA is paid as a top-up to FTB Part A, the same care percentage applies. With 50/50 care of one child:
- Each parent's FTB-A entitlement is at 50%, and any RA loaded onto FTB-A is also at 50%.
- The "number of children for RA purposes" counts shared-care kids fractionally — important because RA's maximum amount steps up at 1+ children and again at 3+ children. A 50/50-shared single kid counts as 0.5 for the family-size bracket, which might not get you over the threshold.
- Your own rent + household composition still drive the RA calc — RA is income-tested via FTB-A, so the same income test logic applies.
Newborn Supplement and shared care
The Newborn Supplement ($2,125.76 for first child, $709.80 subsequent, paid over 13 weeks) loads on top of FTB-A. It's apportioned the same way:
- 50/50 shared-care newborn → each parent gets ~50% of the supplement.
- The Newborn Upfront Payment ($708) is also apportioned.
- Each parent's eligibility (being on FTB-A, not also claiming PPL for the same child) is assessed separately per household.
Maintenance Income Test — when child support feeds back into FTB-A
If you're the parent RECEIVING child support, it feeds into the Maintenance Income Test (MIT) for FTB Part A. Above the MIFA threshold, every $1 of child support received reduces your FTB-A by 50¢ — floored at the base rate. So increasing your child support payments doesn't translate dollar-for-dollar into higher household income — half of it can be lost to reduced FTB-A. (Detail in our Maintenance Action Test guide.)
For the paying parent: child support PAID is deducted from your ATI for FTB purposes, which can move your FTB-A entitlement upward.
Why mismatched reporting causes EOFY surprises
The biggest source of debt letters for shared-care families: reporting different care percentages to different agencies. Common pattern:
- You report 50/50 care to Child Support Agency (CSA) because that's what you and your ex agreed.
- You report 60/40 care to your CCS provider because that's what the actual daycare attendance pattern looks like.
- At EOFY, the FTB system reconciles using one of those numbers (depending on what you told FTB), and the discrepancy with the OTHER system flags an inconsistency review.
The fix: keep one consistent care percentage in your records, supported by your parenting plan / court order / signed agreement. Report the SAME percentage to CSA, to your FTB claim, and to your CCS enrolment. If actual attendance shifts (e.g. the child stays with you an extra night a week because of work), update all three at the same time.
When you need a formal arrangement vs informal
Services Australia can act on:
- Court orders — strongest evidence; binding.
- Parenting plans — written, signed by both parents; non-binding but evidentially strong.
- Verbal / informal arrangements — Services Australia can use other evidence (calendars, school records, statements from teachers/coaches) but disputes are more likely.
If your care arrangement isn't documented, Services Australia can apply the percentage they think is right based on the evidence available, which may not match your actual pattern. Worth documenting even when you and your ex are getting on well — it protects both parents.