How Child Support Is Calculated

In the United States, states regulate the payment of child support through civil statutes, but use different formulas for calculating child support. Most states, including California, Michigan, New York, and Ohio, use what is called the income shares model. Only a few states, including Texas and Alaska, use the percentage of income model. The District of Columbia and Massachusetts use a combination of the income shares and percentage of income models. Only three states, Hawaii, Delaware, and Montana, use the Melson formula.

Income Shares Model

In income shares states, the court bases the child support payment on the income of both parents and the number of children. For example, if a non-custodial parent has a net income of $2,500 a month and the custodial parent has an income of $2,000 a month, the parents' total monthly income is $4,500, Using an economic table that shows the expected cost of raising children, the court will determine that the total monthly child support obligation is $1,125 for one child. The non-custodial parent’s income is approximately 55.6 percent of the parents’ total income and the custodial parent’s income is 44.4 percent. Therefore, the non-custodial parent would pay $625.50 a month in support, or 55.6 percent of the total obligation of the parents.

Percentage of Income Model

In percentage of income states, the court bases the child support payment on a specific percentage of the non-custodial parent’s gross or net income and the number of children the parent supports. The percentage of income can be flat or varying. In flat states, the percentage of income does not change even if the non-custodial parent’s income fluctuates. In varying states, the percentage of income changes when the non-custodial parent’s income fluctuates.

For example, a non-custodial parent has a net income of $2,500 a month and one child to support. Only the non-custodial parent’s income is considered. The flat percentage of the non-custodial parent’s income that must be dedicated to child support is 25% percent for one child. The non-custodial parent will pay $625 a month.

Melson Formula

In Melson formula states, the court bases the child support payment on a defined set of factors, which include the needs of the child and standard of living adjustment (SOLA) for the child. The Melson formula is a variation on the income shares model. It allows more money for child support as one or both parents increase their income. The calculations for child support payments in Melson formula states are more complex than either the income shares or percentage of income model..

Court Discretion

A court has the power to deviate from the state’s standard model and base child support payments on other factors, including the needs of the child, the child’s standard of living before the parents’ separation or divorce, the ability of the non-custodial parent to pay, the needs and income of the custodial parent, and the amount of time that the child spends with the paying parent. Courts may also consider whether a paying parent pays child support for two or more families under two or more child support orders, separation or divorce agreements between parents, and the child’s own resources, such as a trust or inheritance.