Child Support Office

Child Support Guides

Every guide on this site in one place — how paternity gets established, how the guideline amount is calculated, how to request a modification, when support ends, and how interstate cases work. Each one links out to the state pages themselves so you're always working from the current information.

All Guides

Establishing Paternity

How unmarried parents establish legal paternity in every state — the voluntary acknowledgment process, court-ordered genetic testing, and how long you have to rescind it.

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Calculator & Guidelines

See which calculation model your state uses — Income Shares, Percentage of Income, or the Melson Formula — with a link to your state's official guidelines.

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Modify an Order

See what counts as a substantial change and how to request a review of a child support order in your state.

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When Support Ends

Find the age child support ends in your state, and how high school enrollment, disability, or college can extend or shorten it.

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Interstate Cases

Understand how UIFSA governs jurisdiction, enforcement, and modification when parents live in different states.

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Where to Start

Not every case touches all five guides, but for a new case, this is roughly the order they come up in.

  1. 1. Establish Paternity

    For unmarried parents, this comes first — a support order can't issue until legal paternity is on file, either through a signed acknowledgment or a court-ordered genetic test.

  2. 2. Calculate the Guideline Amount

    Every state uses one of a few calculation models to set the starting support amount, based on both parents' income.

  3. 3. Modify It When Things Change

    An order isn't permanent — income, custody, or a child's needs can change enough to warrant a review and recalculation.

  4. 4. Know When It Ends

    The default termination age varies by state, and high school enrollment, disability, or college can extend it.

  5. 5. Handle It Across State Lines

    If the parents live in different states, UIFSA determines which state actually has authority over the case.