Care Percentage Calculator — How Care Nights Affect Child Support in Australia
Care Percentage Calculator — How Care Nights Affect Child Support in Australia
Every overnight stay your child spends with you directly affects how much child support you pay or receive. Services Australia uses a care percentage — calculated from the number of nights per year — to determine each parent's "cost percentage" and ultimately the child support assessment. Getting the care-night count right can mean a difference of hundreds of dollars per month.
How Care Percentage Is Calculated
Services Australia counts the number of nights per year the child spends with each parent (out of 365). That night count converts to a care percentage:
- 52 nights = approximately 14% care
- 128 nights = approximately 35% care
- 176 nights = approximately 48% care
- 189 nights = approximately 52% care
The percentage is then mapped to the Care and Cost Table — a statutory lookup that determines how much of the child's costs you're considered to be meeting directly through day-to-day care.
The Care and Cost Table Thresholds
| Care Percentage | Nights Per Year | Care Level | Cost Percentage |
|---|---|---|---|
| 0–13% | 0–51 | Below regular care | 0% |
| 14–34% | 52–127 | Regular care | 24% |
| 35–47% | 128–175 | Shared care | 25% + 2% per point over 35% |
| 48–52% | 176–189 | Shared care (equal) | 50% |
| 53–65% | 190–237 | Shared care (majority) | 51% + 2% per point over 53% |
| 66–86% | 238–313 | Primary care | 76% |
| 87–100% | 314–365 | More than primary care | 100% |
The critical thresholds that parents should understand:
52 nights (14%) — the "regular care" threshold. Below this, your cost percentage is 0% and you pay the full formula amount. Once you cross 52 nights, your cost percentage jumps to 24%, reducing your child support obligation significantly.
128 nights (35%) — the "shared care" threshold. At this point, you're credited with 25% of costs and the formula starts scaling 2% for every additional percentage point of care. This is also the threshold for eligibility for Family Tax Benefit Part A — below 128 nights, you receive no FTB Part A for that child.
176 nights (48%) — effective equal care. Your cost percentage is 50%, and child support is calculated purely on income difference.
What Counts as an "Overnight"
Services Australia defines a night of care as the parent who has care of the child between midnight and the following midnight. This means:
- A weekend from Friday 4pm to Sunday 4pm counts as two nights (Friday and Saturday)
- Picking the child up from school on Monday and returning them Tuesday morning counts as one night (Monday)
- A midweek dinner visit with no overnight stay counts as zero nights
Services Australia can also consider "actual care" versus "regular care patterns." If you have a parenting plan that says every-other-weekend but the child has been consistently staying additional nights, the actual care pattern may override the written agreement for assessment purposes.
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How Care Nights Feed Into the Child Support Formula
The child support formula works through eight steps, but the care percentage is the pivot:
- Each parent's adjusted taxable income (ATI) minus the self-support amount ($28,463 in 2025-26) and dependent deductions gives their child support income (CSI)
- The combined CSI determines each parent's income percentage
- The income percentage minus the cost percentage gives the child support percentage
- If positive, that parent pays; if negative, they receive
Practical example: Parent A earns $90,000 ATI and has the child 40% of nights (146 nights). Parent B earns $55,000 ATI and has the child 60% of nights. Parent A's cost percentage at 40% care is 35% (25% + 2% × 5). Parent A's income percentage is higher due to income, so Parent A pays — but the 35% cost credit significantly reduces the amount versus a 24% credit at regular care (127 nights).
Impact on Family Tax Benefit
The care percentage affects more than child support:
- FTB Part A — requires at least 35% care (128 nights). If both parents meet the threshold, FTB is split proportionally.
- FTB Part B — available to the primary carer, typically the parent with more than 65% care.
- Child Care Subsidy — a parent with at least 14% care can claim CCS for childcare used during their allocated time.
Disputing the Care Assessment
If you disagree with Services Australia's care percentage determination, you can:
- Provide evidence of the actual care pattern (diary records, messages, school pickup logs)
- Lodge an objection with Services Australia within 28 days of the decision
- If the objection fails, apply for review by the Administrative Review Tribunal
For a detailed breakdown of how parenting time affects your child support assessment and how to structure your care schedule around these thresholds, the NSW Custody & Parenting Plan Guide includes a care-night calculator worksheet and the complete formula walkthrough.
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