1. The 40% Threshold
Section 9 of the Federal Child Support Guidelines applies when each parent has physical custody of the children at least 40% of the time. This works out to approximately 146 days per year.
Important Notes on the 40% Rule
- The threshold is strictly interpreted (39% is NOT shared custody)
- Time is calculated based on actual parenting time, not scheduled time
- Overnight stays are typically how courts measure time
- Holiday and vacation time counts toward the calculation
2. How Shared Custody Support is Calculated
Unlike sole custody situations where table amounts apply directly, shared custody involves more discretion. Courts must consider three factors under Section 9:
Table Amounts
What each parent would pay under the standard tables based on their income and number of children.
Increased Costs
Shared custody creates increased costs as both homes must be fully equipped for children.
Child's Circumstances
The actual conditions, means, needs, and other circumstances of the children.
3. The Offset Method
The most common approach is the "straight offset" or "simple set-off" method:
Example Calculation
Two children, 50/50 custody:
- Parent A earns $100,000 → Table amount: $1,486/month
- Parent B earns $60,000 → Table amount: $910/month
- Offset: Parent A pays Parent B $576/month
Courts may adjust this amount based on the other Section 9 factors, but the offset method is the starting point in most cases.
4. Section 7 Expenses in Shared Custody
Special expenses are still shared proportionally to income, regardless of parenting time. Common Section 7 expenses include:
- Childcare costs
- Extracurricular activities
- Medical and dental expenses not covered by insurance
- Educational expenses
5. Factors Courts Consider
Beyond the offset calculation, courts look at:
- Each parent's actual child-related expenses
- Whether one parent bears disproportionate fixed costs
- The children's standard of living in each home
- Any hardship the support amount would cause