Child Support Calculator

Two formulas dominate US child support law. The Income Shares Model, used by 38 states (including Colorado, Virginia, Pennsylvania, Ohio, Florida, New Jersey, Illinois, and most others), starts by combining both parents' incomes, looks up a basic support amount that intact families at that income level typically spend on children, then splits that amount pro-rata by each parent's share of combined income. The Percentage of Income Model, used by Mississippi, Nevada, Wisconsin, North Dakota, Texas (in modified form), and Alaska, ignores the recipient parent's income entirely and applies a flat percentage to the payer's income (Wisconsin: 17 percent for one child, 25 percent for two, 29 percent for three). Delaware and Hawaii use a third hybrid called the Melson Formula. This calculator uses the Income Shares Model because it is the dominant national approach and produces more equitable orders when both parents earn meaningful income.

No. This is a planning estimate, not legal advice. Real child-support orders depend on your state's official worksheet (which uses different schedule numbers than the representative composite here), judicial deviations, imputed income for unemployed or underemployed parents, self-support reserves, extraordinary medical or educational expenses, prior support obligations, and tax filing status. Two cases with identical incomes can produce orders that differ by hundreds of dollars per month between states or even between counties. Use this calculator to ballpark the range before negotiation or mediation, but file with your state's official worksheet and a family-law attorney before signing or paying anything.

Each state uses its own schedules, income definitions, self-support reserve, custody adjustment, add-on expenses, caps, and judicial deviations. The calculator's representative formula is not calibrated to any current state worksheet and cannot rank states reliably. Use the official worksheet and current rules for the state with jurisdiction.

An overnight is not universally defined as a full 24-hour period. State worksheets may count nights, days, or parenting-time equivalents under their own rules. The calculator uses a simple annual overnight count and a 100-night internal threshold. That threshold is not a current legal rule for any specific state.

In this calculator, the adjustment starts above 100 entered overnights and grows linearly, capped at a 50 percent reduction. That is an internal model, not a federal standard or a substitute for a state's shared-custody worksheet. A real order can use a different threshold, formula, expense allocation, or no automatic reduction.