Your percentage of care is a key factor in a child support assessment. Use this calculator to work out the proportion of nights your child spends in your care.
It's simple to use and provides an accurate result when used properly. Ideally, both parents should agree on the care percentage before applying for or updating child support.
Why this calculator works differently
Services Australia allows parents to manually select individual holiday nights for a specific year. That approach can be precise, but it is time-consuming and hard to apply consistently. This calculator takes a simpler approach by letting you enter the total number of overnight stays outside the normal schedule, such as annual holidays.
In most cases, the ongoing schedule is what matters most. Holiday adjustments typically make only a small difference unless care is close to 50%.
What is the Care Percentage?
The care percentage is calculated by dividing the number of nights a child stays with a parent by the total number of days in the care period. The formula is:
Care Percentage = (Number of nights in parent's care / Total days in the care period) x 100
The percentage is normally based on actual care provided. If the care percentage isn't a whole number, it is rounded up if over 50%, and down if below 50%.
Refer to Subdivision B—Determination of percentage of care in the Child Support (Assessment) Act 1989 for details.
Care Percentage Table
Here's how the number of regular overnights translates into the percentage of care.
| Parent A (care each fortnight) |
Parent A (%) |
Parent B (care each fortnight) |
Parent B (%) |
|---|---|---|---|
| 0 nights | 0% | 14 nights | 100% |
| 1 night | 7% | 13 nights | 93% |
| 2 nights | 14% | 12 nights | 86% |
| 3 nights | 21% | 11 nights | 79% |
| 4 nights | 28% | 10 nights | 72% |
| 5 nights | 35% | 9 nights | 65% |
| 6 nights | 42% | 8 nights | 58% |
| 7 nights | 50% | 7 nights | 50% |
The table shows that 2 nights per fortnight is 14% care, 3 nights per fortnight is 21%, 4 nights per fortnight is 28%, and so on. However, the actual credit you receive for providing care usually differs somewhat from your percentage of care.
These percentages don't account for holidays. Factoring in holidays typically increases the care percentage for the parent with less than 50% care.
Due to an unusual rounding method in Australia, you may get slightly different results compared to a normal care estimator. A custody calculator such as the free calculator at Custody Page may be more suitable for child support cases outside Australia.
Cost Percentage Table
Here's how the child support formula translates your care percentage into a cost percentage.
| Nights of care (per fortnight) |
Percentage of care (% range) |
Cost percentage (setting or method) |
Cost percentage (formula %) |
|---|---|---|---|
| Less than 2 nights | 0% to 13% | Nil | 0% |
| 2 to 4 nights | 14% to 34% | 24% | 24% |
| 5 to 6 nights | 35% to 47% | 25% plus 2% for each percentage point over 35% | 25% to 49% |
| Around 7 nights | 48% to 52% | 50% | 50% |
| 8 to 9 nights | 53% to 65% | 51% plus 2% for each percentage point over 53% | 51% to 75% |
| 10 to 12 nights | 66% to 86% | 76% | 76% |
| 13 to 14 nights | 87% to 100% | 100% | 100% |
The table highlights how the child support formula translates your care percentage into a cost percentage. CSA and Centrelink don’t assume that the percentage of costs you incur as a parent is equal to your percentage of care.
- Less than 2 nights a fortnight (<1 night a week): Zero credit for child-related spending.
- 2, 3, or 4 nights per fortnight (1-2 nights a week): You get 24% credit for child-related spending.
- 5 or 6 nights (2.5 to 3 nights a week): While providing 35-48% of care, you receive credit for 25-49%.
- 7 nights (3.5 nights a week): 50% cost percentage.
- 8 or 9 nights (4 to 4.5 nights a week): A 51% to 75% cost percentage, depending on the exact care percentage.
- 10 to 12 nights (5-6 nights a week): 76% credit for the costs of raising children.
- 13 or 14 nights (6.5 to 7 nights a week): 100% credit for child-related costs.
Source: Section 55C of the Child Support (Assessment) Act 1989.
Related: How Child Support is Calculated