States generally use one of three models to determine the base child support amount due. Explanations of each model and the states that use them follow.
The Income Shares Model is based on the concept that the child should receive the same proportion of parental income that he or she would have received if the parents lived together. In an intact household, the income of both parents is generally pooled and spent for the benefit of all household members, including any children. Forty-one states, Guam and the Virgin Islands use the income shares model: Alabama, Arizona, Arkansas, California, Colorado, Connecticut, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Nebraska, New Hampshire, New Jersey, New Mexico, New York, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Utah, Vermont, Virginia, Washington, West Virginia, Wyoming, Guam, Virgin Islands.
The Percentage of Income Model sets support as a percentage of only the noncustodial parent's income; the custodial parent's income is not considered. This model has two variations: the Flat Percentage Model and the Varying Percentage Model. Six states (Alaska, Mississippi, Nevada, North Dakota, Texas, Wisconsin) use the percentage of income model. Four states (Alaska, Mississippi, Nevada and Wisconsin) use the flat percentage model while the other two states (North Dakota and Texas) use the varying percentage model.
The Melson Formula is a more complicated version of the Income Shares Model, which incorporates several public policy judgments designed to ensure that each parent's basic needs are met in addition to the children's. The Melson Formula was developed by a Delaware Family Court judge and fully explained in Dalton v. Clanton, 559 A.2d 1197 (Del. 1989). Only three states (Delaware, Hawaii and Montana) use the Melson Formula.
The District of Columbia uses a hybrid model that starts as a varying percentage of income model and is then reduced by a formula based on the custodial parent's income. Use the links in the chart below to view these guidelines.
All of the guideline models have certain aspects in common. First, most of the guidelines incorporate a "self-support" reserve for the obligor. Second, all the guidelines have a provision relating to imputed income. Third, by federal regulation, all the guidelines take into consideration the health care expenses for the children, by insurance or other means. Lastly, most of the guidelines have incorporated into the presumptive child support formula special additions for child care expenses, special formulas for shared custody, split custody, and extraordinary visitation, and special deductions for the support of previous and subsequent children.