Child Support Map · 50 state guides

Child support

Child support in every state: how the amount is figured, how to open a case with the state agency, how to change an order, how unpaid support is collected and when support ends, with an estimator for percentage states and free letters.

What it is

Child support is money a parent pays to help cover a child's living costs after the parents separate or if they never lived together. Each state sets the amount with its own guideline formula, usually from the parents' incomes and the number of children; many states also count the time each parent spends with the child. Every state has a child support agency that can find the other parent, establish paternity, set an order, take support from paychecks and collect unpaid support, for a small fee or none. When the case is with the agency, either parent can ask for a review of the order every 3 years, or sooner after a big change such as a lost job. Past-due support can't be lowered later, so changes must be asked for as soon as things change. Support usually ends at 18, later in some states.

Who it helps

  • Parents who need to open a child support case
  • Parents who want to change an order after a job loss or a raise
  • Parents owed past-due support
  • Parents who pay support and want to know when it ends

Go straight to your state's guide

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Across the country

50state guides checked against official sources so far (New Hampshire: a link to the state's child support agency until its guide is checked)
40of them use the income-shares model, where both parents' incomes count
7use a percentage of income, including Alaska, Mississippi, Nevada and 4 more
3use the Melson formula: Delaware, Hawaii and Montana
42states end support at 18 as the general rule (often later if the child is still in high school); it runs to 21 in District of Columbia, Mississippi and New York
12%the highest fixed yearly interest on unpaid support in our guides, in Missouri, Rhode Island and Washington; other states charge less, a variable rate or none

Figures from Child Support Map's state data, checked Oct 2026.

Guides and comparison tables

All of Child Support Map: every state, tools and guides.

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