How child support is calculated

How does income shares work?

Income shares means each parent pays a share of one combined support amount. The guideline uses a schedule—a table matching income and the number of children to a basic support need. That basic amount is not necessarily the final payment.

Illinois sets out the sequence in 750 ILCS 5/505: determine each parent’s monthly net income, combine it, select the schedule amount, and calculate each parent’s percentage share. Florida also combines net incomes under F.S. 61.30. Its schedule lists $190 a month for one child at combined monthly net income of $800.

Extra expenses and parenting time can change the result under the state’s rules. Florida adds qualifying child care under F.S. 61.30; Pennsylvania accounts for child care, health insurance, and unreimbursed medical expenses under Rule 1910.16-4. The worked example and line-by-line worksheet show how the selected state applies its rules.

• Combine the income each state counts.
• Find the schedule amount for that income and number of children.
• Calculate each parent’s percentage share.
• Account for allowed add-ons, such as qualifying child care.
• Apply the state’s parenting-time adjustment, if applicable.

Which states use the paying parent’s income?

Texas, Wisconsin, and Nevada use percentage-of-income guidelines, but they do not use the same income definition or rates. Texas starts with net resources; Wisconsin and Nevada start with gross income. A percentage from one state cannot be transferred to another.

Under Texas Family Code §154.125, the standard rates below apply within the guideline maximum and at or above the low-income threshold. Texas also provides multiple-family and low-income multiple-family tables under §154.129. The Texas calculation page explains the state-specific calculation.

Wisconsin’s Department of Children and Families publishes percentage standards under DCF 150. Nevada uses tiered rates under NAC 425.140: each rate applies only to the income portion in that tier, not to all income.

• Texas: 20% for one child, 25% for two, 30% for three, 35% for four, and 40% for five. For six or more, not less than the amount for five.
• Wisconsin: 17% for one child, 25% for two, 29% for three, 31% for four, and 34% for five or more.
• Nevada tiers: the first $6,000 of monthly gross income; the portion above $6,000 through $10,000; and the portion above $10,000.
• Nevada, one child: 16%, 8%, and 4% across those tiers.
• Nevada, two children: 22%, 11%, and 6%.
• Nevada, three children: 26%, 13%, and 6%.
• Nevada, four children: 28%, 14%, and 7%.

How does New York use combined income?

New York uses a percentage of combined parental income rather than a basic support schedule. Domestic Relations Law §240 sets 17% for one child, 25% for two, 29% for three, 31% for four, and no less than 35% for five or more. Its income calculation starts with gross income.

The percentages alone are not a complete payment calculation. Under §240, qualifying child care is allocated in proportion to parental income and added separately; see the New York calculation page for the state worksheet.

How does California’s formula work?

California Family Code §4055 states the formula as CS = K[HN − (H%)(TN)]. In plain words, both parents’ net incomes and the parenting-time share work inside the formula. It is not a flat percentage of the paying parent’s income.

The income factor also varies by total monthly net disposable income under §4055. California separately requires qualifying employment-related or employment-training child care as additional support under §4062 unless already included in the calculation. The California calculation page explains the formula alongside the worksheet.

Is support based on gross or net income?

The answer depends on the state. Gross income is income before deductions; net income reflects the deductions the guideline permits. A guideline’s net-income figure is not necessarily the same as take-home pay.

Florida uses net income under F.S. 61.30, while Virginia uses gross income under Code §20-108.2. Texas uses net resources under §154.125. For a Texas health or dental coverage deduction, §154.062 provides a cost-allocation rule when the same plan covers other minor dependents.

There is no nationwide deduction list. The state calculation pages identify the governing rule and available official calculators, worksheets, and forms. Where an edition’s effective date has not been confirmed, it is being verified rather than assumed.

Can the ordered amount differ?

The guideline is a legal starting point, not an automatic final order. Illinois calls it a rebuttable presumption: the calculated amount is presumed correct, but that presumption can be challenged. Under 750 ILCS 5/505, a departure requires written findings explaining the reasons and stating the guideline amount.

Florida’s listed deviation factors under F.S. 61.30 include extraordinary medical or educational expenses, special needs, seasonal income changes, available assets, and tax-credit effects. Texas requires findings when an order varies from its percentage guidelines under §154.130. Nevada likewise requires findings and the guideline amount under NAC 425.100.

A formula adjustment is different from a deviation. For example, Ohio generally requires a 10% reduction when court-ordered parenting time reaches 90 overnights a year under §3119.051, subject to that section’s exceptions. State agencies, court self-help centers, and legal aid can explain available free help with the applicable process.