Care Percentage Calculator
Work out your child support care percentage in under two minutes. Enter how many nights your child spends with you, whether per fortnight, per week, or by using our interactive calendar.
The calculator will calculate your care percentage, care level, and cost percentage in line with the official Australian Government formula. Both parents’ figures are displayed side by side, along with a clear, step-by-step breakdown showing exactly how each number is calculated.
For a full estimate of how much child support may be payable or received, you can also use our:
Care Percentage Calculator
Estimate your care percentage based on the Australian child support formula
Your Care Estimate
Based on your care arrangement
| Care % | Care Level | Cost % |
|---|---|---|
| 0% – 13% | Below Regular Care | 0% |
| 14% – 34% | Regular Care | 24% |
| 35% – 47% | Shared Care | 25% + 2×(care%−35) |
| 48% – 52% | Shared Care (Equal) | 50% |
| 53% – 65% | Shared Care | 51% + 2×(care%−53) |
| 66% – 86% | Primary Care | 76% |
| 87% – 100% | Above Primary Care | 100% |
Care percentage calculations are based on overnight care patterns projected over a 12-month period. The actual care percentage determined by Services Australia may differ based on detailed care records, interim periods, and the Registrar's discretion under the Child Support (Assessment) Act 1989.
Rounding follows the Section 54D methodology: percentages below 50% are rounded down; percentages of 50% or more are rounded up. Cost percentages are determined under Section 55C.
You should always verify your situation directly with Services Australia or seek independent legal advice before making financial decisions based on these estimates.
What is a Care Percentage?
Your care percentage is a number that represents how much time your child spends living with you over a 12-month period. Services Australia uses this figure in the child support formula to work out who pays child support and how much they pay.
The calculation itself is straightforward. You take the number of nights your child stays with you during the care period, divide that by the total number of days in the period (usually 365), and multiply by 100.
For example, if your child stays with you 130 nights out of 365 days, your care percentage is approximately 35%.
Care percentage is determined under Part 5 of the Child Support (Assessment) Act 1989 (Cth), and it feeds directly into the cost percentage and, ultimately, the amount of child support payable.
Key Thresholds to Be Aware Of
Certain care percentage thresholds trigger significant changes in the child support formula. If you are near one of these boundaries, even a single extra night of care can change the outcome.
The 14% Threshold Below Regular to Regular Care
At 13% care (approximately 47 nights), your cost percentage is 0%. At 14% care (approximately 52 nights), it jumps to 24%. There is no gradual transition, the difference of just five nights over a full year can change the amount of child support by thousands of dollars annually.
The 35% Threshold Regular to Shared Care
Moving from 34% to 35% care takes you from a flat 24% cost percentage to a sliding scale starting at 25%. While the immediate dollar impact is smaller than the 14% threshold, entering shared care also affects eligibility for Family Tax Benefit Part A.
The 48% Threshold Shared to Equal Care
Reaching 48% care gives you a flat 50% cost percentage. If both parents earn similar incomes and share care equally, this can result in little or no child support payable in either direction.
The 66% Threshold Shared to Primary Care
Crossing from 65% to 66% care moves your cost percentage from a sliding scale figure to a flat 76%. This generally solidifies the other parent’s position as the child support payer.
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