What is the difference between income-shares and percentage-of-income models?

Income-shares combines both parents' incomes, finds the total support a child would receive in an intact household, and splits it in proportion to each parent's share of income. Percentage-of-income applies a flat percentage to only the paying (obligor) parent's income, ignoring the other parent's earnings.

Which states use which model?

Most states — including California, New York, and Pennsylvania — use a form of income-shares. A handful, such as Texas, Wisconsin, and Mississippi, use percentage-of-obligor-income. This tool maps each listed state to its general model, but exact tables and add-ons vary.

How do custody overnights affect the amount?

In income-shares states with shared-parenting adjustments, more overnights for the paying parent reduces the transfer because that parent already covers more direct costs. This tool applies a simple proportional credit; many states use a stepped formula that differs in detail.

Does this include childcare and medical costs?

It adds work-related childcare as a shared add-on split by income share in income-shares mode. It does not model health insurance premiums, extraordinary medical expenses, or tax effects, which most guidelines treat separately.

Can I rely on this for a court filing?

No. It is a planning estimate to set expectations before mediation. Official guideline worksheets, state-specific tables, deviation factors, and judicial discretion produce the binding number — always run your state's official calculator or consult counsel.

Child Support Estimator by State

A child support estimator applies your state’s statutory guideline to gross parental incomes, the number of children, and the custody arrangement to approximate a monthly obligation. States fall into two broad camps: most use an income-shares model, and a minority use a percentage-of-obligor-income model. This tool selects the right approach for the state you choose and produces a guideline-style estimate, including a shared childcare add-on.

How it works

In income-shares states the calculation combines both parents’ gross monthly incomes. A child-count percentage of that combined income approximates the total support the children would receive if the household were intact. Each parent’s obligation is their share of combined income times that total. The paying parent is the one with fewer custody overnights, and their transfer is reduced by a credit proportional to the share of overnights they already cover.

In percentage-of-income states the formula is simpler: a flat statutory percentage — for example Texas’s 20% for one child, 25% for two, rising to 40% for five or more — is applied to the obligor parent’s net resources only. The other parent’s income does not enter the base figure.

Income-shares: obligation = combined income share × guideline total, less an overnight credit. Percentage model: obligation = statutory percent × obligor income.

Example and notes

Two parents earn $4,000 and $2,000 gross monthly in an income-shares state with two children. Combined income is $6,000; a representative two-child rate yields a total obligation, split two-thirds to the higher earner. If that parent has the fewer overnights, their share — minus an overnight credit and plus their portion of childcare — is the estimated transfer.

Real guidelines layer in self-support reserves, health-insurance credits, extraordinary expenses, low-income adjustments, and judicial deviation. This estimator deliberately stays at the guideline-skeleton level so you can sanity-check a number before mediation — always confirm with your state’s official worksheet.