Why Every State Uses a Formula
Federal law requires each state to adopt child support guidelines that are presumed to produce the correct amount of support, and to review them at least every four years (42 U.S.C. § 667). A judge can depart from the guideline amount only by explaining why applying it would be unjust or inappropriate in that case.
The Main Calculation Models
| Model | How it works | Used in |
|---|---|---|
| Income shares | Combines both parents' incomes, estimates what the parents would have spent on the child if they lived together, and divides that amount by each parent's share of income | Most states |
| Percentage of income | Support is a set percentage of the paying parent's income, based on the number of children | A minority of states |
| Melson formula | A variation of income shares that first reserves a self-support amount for each parent | Delaware, Hawaii, Montana |
What Goes Into the Calculation
- Income of each parent, usually gross income from wages, self-employment, bonuses, commissions, and some benefits. Many states allow deductions for taxes or other support obligations.
- Imputed income if a parent is voluntarily unemployed or underemployed. The court can assign income based on what the parent could earn.
- Parenting time. Many states reduce support when the paying parent has the children for a significant share of overnights.
- Number of children covered by the order.
- Add-ons such as health insurance premiums, uninsured medical costs, work-related child care, and sometimes education expenses.
Most states publish an official calculator or worksheet so parents can estimate the amount.
How Long Child Support Lasts
In most states, support continues until the child turns 18, or until the child graduates from high school if that happens later, often with a cutoff around age 19. Some states extend support longer, and support for an adult child with a disability may continue indefinitely. A few states allow orders for college expenses.
Enforcement Tools
Every state has a child support agency that helps parents establish paternity, set orders, and collect payments, often at little or no cost. Enforcement tools include:
- Income withholding directly from the paying parent's paycheck, which is the default for most orders
- Interception of federal and state tax refunds
- Suspension of driver's, professional, and recreational licenses
- Passport denial when arrears exceed $2,500
- Liens on property and reporting to credit bureaus
- Contempt of court, which can include jail
- Federal prosecution for willfully failing to pay support for a child in another state in certain cases (18 U.S.C. § 228)
Changing a Support Order
Either parent can ask to modify support when there is a substantial change in circumstances, such as a significant change in income, job loss, a change in custody, or new medical needs. States must also allow a review at least every three years on request for cases handled by the child support agency.
Changes usually apply only from the date the modification request was filed, so a parent who loses a job should file promptly rather than wait.
Taxes
Child support is not taxable to the parent who receives it and not deductible by the parent who pays it. Which parent may claim the child for tax benefits is a separate question governed by IRS rules and the divorce or custody order.
