The method, step by step

How is child support calculated?

Child support is calculated by applying a state formula to the parents’ incomes: work out each parent’s income as the state defines it, apply the state’s schedule or percentage for the number of children, then adjust for parenting time, health insurance, child care and low incomes. In Texas, for example, one child is 20% of the paying parent’s net resources.

Child Support by State editorial teamUpdated 8 sources

The six steps every state follows

Every state calculates child support with a written guideline that produces a number; federal law requires it and makes that number the presumed correct amount.[1][2] The steps are the same everywhere, even though each state fills them in differently:

  1. Income. Decide whose income counts and in what form: gross, net, or something in between.
  2. Basic obligation. Apply the state’s schedule, percentage or formula for the number of children.
  3. Division. In most states, split the basic obligation by each parent’s share of combined income.
  4. Parenting time. Adjust for overnights, if the state has a formula for it.
  5. Add-ons. Add child care, the children’s health insurance and sometimes extraordinary costs, split by income.
  6. Limits and deviations. Apply the low-income adjustment and any income cap; the court may then deviate with written findings.[2]

Step 1: what counts as income

Income means income from all sources in every state, but states differ on whether taxes come off first.

Income base by state (2026)
Income baseStates
Gross incomeGeorgia, North Carolina, Ohio
Net income (after taxes)Florida, Pennsylvania, California (“net disposable income”)
Gross converted to net with an official tableTexas (2026 tax charts), Illinois (HFS gross-to-net table)
Gross minus FICA and local tax onlyNew York

Means-tested benefits such as SSI and TANF are excluded everywhere we cover, and a parent who is voluntarily unemployed can have income imputed, but only after the court considers their actual circumstances; incarceration cannot be treated as voluntary unemployment.[2]

Step 2: the basic obligation and child support percentages

The basic obligation comes from one of three kinds of formula: income shares (44 states), a percentage of the paying parent’s income (3 states) or the Melson formula (3 states).[4] States choose their own model.[3]

  • Percentage of income. Texas applies 20% of net resources for one child, 25% for two and up to 40% for five or more, to the first $11,700 a month.[5]
  • Income shares. North Carolina’s schedule gives $1,614 a month for two children at $7,000 of combined gross income.[8]
  • Percentage of combined income. New York applies 17% to 35% to combined income and divides it by income share.

For more on the most common model, see the income shares model explained.

Step 3: dividing it between the parents

In income shares states, each parent owes the basic obligation times their percentage of combined income; the parent the children live with is presumed to spend their share directly.[4] In the North Carolina example, a parent earning $4,000 of the $7,000 combined pays 57.14% of $1,614, or $922.29 a month.[7]

Step 4: parenting time

Parenting time lowers support in most states once a threshold of overnights is reached, from 73 a year in Florida to 146 in Illinois; Georgia and California adjust continuously, and Texas and New York have no formula. Our page on 50/50 custody child support compares every rule.

Steps 5 and 6: add-ons, low incomes and deviations

Child care for work and the children’s health insurance are added and split by income in most states.[7] Every guideline must also protect a low-income parent’s basic needs, for example with a self-support reserve, and a court can order a different amount only with written findings that the guideline amount is unjust or inappropriate.[1][2]

A worked Texas example: $5,000 a month in gross wages becomes $4,199.17 in net resources on the 2026 tax chart, and two children at 25% gives $1,049.79 a month.[6]

See the result for your own state with the child support calculator by state, or compare amounts in how much child support is.

Frequently asked questions

What percentage of income is child support?

Only a few states use a fixed percentage: Texas uses 20% of net resources for one child and 25% for two; New York uses 17% and 25% of combined income. Income shares states use schedules that work out to a falling percentage as income rises.

Is child support calculated on gross or net income?

It depends on the state: Georgia, North Carolina and Ohio use gross income; Florida, Pennsylvania and California use net income; Texas and Illinois convert gross to net with official tables.

Does the custodial parent’s income count?

In income shares states, yes: it lowers the paying parent’s share. In Texas it does not enter the calculation.

What is a child support deviation?

A deviation is an order above or below the guideline amount. Federal rules allow it only with a written or on-the-record finding that the guideline amount would be unjust or inappropriate in the case, stating the guideline amount and the reason for the difference.

Who decides the final amount?

The court, or the child support agency in administrative cases. The guideline amount is presumed correct, but the court can deviate with written findings.

Sources

  1. 42 U.S.C. § 667, State guidelines for child support awards · U.S. Code (GovInfo), 2023 edition
  2. 45 CFR § 302.56, Guidelines for setting child support orders · Electronic Code of Federal Regulations, current text, effective January 19, 2017
  3. Flexibility, Efficiency, and Modernization in Child Support Enforcement Programs; Final Rule, 81 FR 93492 · U.S. Department of Health and Human Services (Federal Register), December 20, 2016
  4. Texas Child Support Guidelines Review Report 2025 (national inventory of guideline models, pp. 13–18) · Office of the Attorney General of Texas, Child Support Division, December 2025
  5. Texas Family Code, Chapter 154 (Child Support) · Texas Legislature, current through the 89th Legislature (2025)
  6. 2026 Tax Charts (Employed and Self-Employed Persons) · Office of the Attorney General of Texas, Child Support Division, tax year 2026
  7. North Carolina Child Support Guidelines (AOC-A-162, Rev. 1/23) · NC Administrative Office of the Courts, published by NC DHHS Child Support Services, effective January 1, 2023
  8. Schedule of Basic Support Obligations (AOC-A-162, Rev. 1/23) · NC DHHS Child Support Services, effective January 1, 2023