What Determines Child Support
Child support is calculated using a state-specific guideline formula rather than a judge's personal discretion, and most states fall into one of three models. The majority — around 41 states, including California, New York, and Texas's underlying framework — use the "income shares" model, which estimates what the child would have received if the parents had stayed together and divides that amount between the parents based on their relative incomes. A smaller group of states, including Alaska, Mississippi, Nevada, North Dakota, and Wisconsin, use a "percentage of income" model that bases support on a set percentage of the paying parent's income alone. A few states — Delaware, Hawaii, and Montana — use the more complex Melson formula, which builds in a basic-needs reserve for both parents before calculating support. Whichever model applies, the actual number is shaped by both parents' gross income, the number of children, healthcare and childcare costs, support obligations for other children, and how many overnights each parent has with the child, since more shared parenting time typically reduces the paying parent's obligation. Because the formula is largely mechanical once the inputs are known, child support is often one of the more predictable pieces of a divorce to resolve.