Child Support Calculator by State

Every state sets its own guideline formula, but they fall into three families. Income-shares states (the large majority, including California, Florida, Georgia, and Illinois) combine both parents' incomes, look up or compute a basic obligation, and split it in proportion to income. Percentage-of-obligor states like Texas apply a flat percentage to only the paying parent's income. New York's CSSA is a hybrid: fixed percentages applied to combined income, then split pro-rata. Parenting time adjusts the result in most states, each with its own formula.

It depends on the state. Texas, California, Florida, and Illinois work from net income (each defining deductions differently — Illinois even publishes a standardized gross-to-net table). Georgia uses gross income before taxes. New York uses gross income minus only FICA and NYC/Yonkers local tax — not federal or state income tax. Using the wrong income basis is the most common estimation error.

Equal time rarely means zero support — most formulas still transfer money from the higher earner. Florida applies a 1.5× gross-up cross-weighted by overnights once a parent has 20% of nights; Illinois has a similar formula at 146 overnights each; Georgia's 2026 rules weight court-ordered days by a 2.5 exponent; California bakes timeshare directly into its algebraic formula. Support generally reaches zero only when both time and incomes are close to equal.

No. They implement each state's published guideline formula, which is a rebuttable presumption — courts can deviate based on statutory factors like extraordinary expenses, a child's special needs, or high incomes. Use the results to understand the ballpark and the drivers, then verify with the state's official worksheet or a family-law attorney before relying on a number.

Six states so far, chosen by search demand: Texas (percentage of net resources), California (SB 343 formula), New York (CSSA percentages with the 2026 $193,000 cap), Florida (§61.30 schedule), Georgia (BCSO table plus the new 2026 parenting-time adjustment), and Illinois (March 2026 income-shares tables). Each state page documents its statute, current parameters, and effective dates. More states are on the way.