Child Support Guides

1. The three guideline models

Every U.S. state uses one of three structures (or a hybrid). Knowing which one applies to you explains why a neighbor in another state can owe a very different amount on the same paycheck.

• Percentage of Income (6 states): a flat or graduated percentage of only the paying parent’s income. Simplest and most predictable — Texas, Wisconsin, Alaska, Mississippi, Nevada, North Dakota.
• Income Shares (41 states + D.C.): both parents’ incomes are added, matched to a schedule of “basic” support, then each parent pays their proportional share. Child care and health insurance are added on top, and significant parenting time can trigger a credit.
• Melson Formula (Delaware, Hawaii, Montana): Income Shares plus a protected self-support reserve for each parent and a standard-of-living adjustment for the child.

2. What “income” actually means

States differ on the basis: some use gross (pre-tax), some net (after taxes and mandatory deductions), and some adjusted gross. This single choice can swing the obligation by 20–30%. Always check your state’s basis before comparing figures, and use the basis our per-state calculator asks for.

3. The inputs that move the number

• Number of children — obligations rise, but usually at a decreasing rate.
• Parenting time (overnights) — in Income Shares states, ~40%+ overnights often reduces the base through a credit.
• Child care & health insurance — typically split in proportion to income, on top of the basic obligation.
• Existing orders / other children — many states deduct support already paid for other households.

Our calculators let you enter these where the model uses them. Start with your state page, then use the comparison tool to see how a move across state lines would change the outcome.