How Child Support Is Calculated
A comprehensive guide to the three main child support models used across the United States, with step-by-step examples.
Key Takeaway
Every US state uses one of three mathematical models to calculate child support. The most important factors are both parents' incomes, the number of children, and custody time splits. Additional costs like healthcare and childcare are typically added to the base amount.
Income Shares Model
The most widely used model. Estimates how much two parents would spend on a child if living together, then divides that obligation proportionally.
How It Works
Example
Parent A earns $4,000/mo, Parent B earns $3,000/mo. Combined = $7,000. For 2 children, basic support might be $1,750. Parent A's share = 57% = $998/mo obligation.
Percentage of Income Model
A simpler approach that applies a fixed percentage directly to the paying parent's income, regardless of the other parent's earnings.
How It Works
Example
Texas: Non-custodial parent earns $5,000/mo net. For 1 child: 20% × $5,000 = $1,000/mo. For 2 children: 25% × $5,000 = $1,250/mo.
Melson Formula
The most complex model. First ensures parents can meet their own basic needs, then calculates the child's needs based on combined remaining income.
How It Works
Example
After reserving $1,200 for parent's own needs, remaining income is calculated. Both parents' shares go into a pool to fund the child's needs at an appropriate standard of living.
Common Add-On Expenses
In addition to the base child support amount, courts typically add these expenses:
Health Insurance
The cost of the child's share of health insurance premiums is divided proportionally between parents.
Medical Expenses
Uninsured or unreimbursed medical, dental, and vision expenses are typically split 50/50 or proportionally.
Childcare Costs
Work-related childcare expenses (daycare, after-school care) are divided based on each parent's income share.
Educational Expenses
Tuition, school fees, tutoring, and supplies may be added to base support or ordered separately.
Frequently Asked Questions
What is the Income Shares Model?
The Income Shares Model estimates how much parents would have spent on the child if they lived together, then divides that obligation proportionally based on each parent's share of combined income. Used by over 40 states.
What is the Percentage of Income Model?
In the Percentage of Income Model, child support is calculated as a fixed percentage of the paying parent's income, regardless of the other parent's earnings. Texas, Wisconsin, and a few other states use this approach.
What is the Melson Formula?
The Melson Formula is a more complex variation used by Delaware, Hawaii, and Montana. It first ensures each parent can meet their own basic needs (self-support reserve), then calculates the child's needs and each parent's share.
Does child support cover college expenses?
In most states, child support obligations end when the child turns 18 or graduates high school. Some states (like New York and Massachusetts) can extend support through college. This must typically be established in the original order or a modification.
How is child support calculated for self-employed parents?
For self-employed parents, courts look at net profit from business, add back non-cash business deductions, and may impute income based on earning capacity. Self-employment makes calculations more complex and contested.
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Disclaimer
This tool provides estimates only and is not legal advice. Child support calculations vary based on specific circumstances, court orders, and state guidelines. Always consult with a licensed family law attorney for advice specific to your situation.
Related Resources
Child Support by State
Find your state's official guidelines and resources
Indiana Child Support Guide
Indiana income shares model explained
California Child Support Guide
California's unique formula explained
Texas Child Support Guide
Texas percentage of net resources model
Average Child Support Payments
National and state averages for support
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