Every state uses one of three formulas to set child support: the income shares model (41 states plus the District of Columbia), the percentage of income model (Alaska, Mississippi, Nevada, North Dakota, Texas, and Wisconsin), or the Melson formula (Delaware, Hawaii, and Montana). Income shares adds both parents' incomes together, finds the total amount a two-parent household at that income would spend on the children, and splits that obligation between the parents in proportion to what each one earns. Percentage of income states ignore the custodial parent's income entirely and apply a flat or sliding percentage to the paying parent's income. The Melson formula is income shares with a self-support reserve carved out first.
Below is the model each state uses, the actual percentages where a state publishes them, and how a child support order interacts with benefits like SNAP, Medicaid, and TANF.
The Three Child Support Models Compared
| Feature | Income Shares | Percentage of Income | Melson Formula |
|---|
| States using it | 41 states + DC | 6 states | 3 states |
| Whose income counts | Both parents | Paying parent only | Both parents |
| Starting point | Combined adjusted income | Paying parent's gross or net income | Each parent's income minus a self-support reserve |
| Self-support protection | Usually a low-income adjustment | Usually a low-income adjustment | Built into the formula as the first step |
| Standard of living bump | No separate step | No | Yes, a percentage of leftover income |
| Complexity | Moderate | Simplest | Most complex |
The income shares model rests on one idea: children should get roughly the same share of parental income they would have received if the parents lived together. States build economic tables (called a schedule of basic child support obligations) that estimate child-rearing spending at each combined income level, then prorate it.
Percentage of income is faster to apply and easier for a self-represented parent to predict, but it produces results that can look unfair when the custodial parent earns far more than the paying parent.
The Melson formula, named after Delaware Family Court Judge Elwood Melson, runs three steps. First, each parent keeps a subsistence amount, typically somewhere around $1,000 per month depending on the state and year. Second, the children's primary needs are covered from what remains. Third, a standard of living adjustment shares a percentage of any leftover income with the children.
Child Support Model by State
| State | Model | Notes |
|---|
| Alabama | Income shares | Rule 32 schedule |
| Alaska | Percentage of income | Civil Rule 90.3, flat percentages |
| Arizona | Income shares | Guidelines revised 2022 |
| Arkansas | Income shares | Switched from percentage of income in 2020 |
| California | Income shares variant | Family Code 4055 algebraic formula |
| Colorado | Income shares | Combined income schedule |
| Connecticut | Income shares | 2026 update raised the income ceiling |
| Delaware | Melson formula | Origin state of the formula |
| District of Columbia | Income shares style | Combined-income based guideline |
| Florida | Income shares | Fla. Stat. 61.30 |
| Georgia | Income shares | Adopted 2007 |
| Hawaii | Melson formula | Includes standard of living adjustment |
| Idaho | Income shares | Rule 126 |
| Illinois | Income shares | Switched from percentage of income July 1, 2017 |
| Indiana | Income shares | Includes parenting time credit |
| Iowa | Income shares | Uses net income |
| Kansas | Income shares | Age-based schedules |
| Kentucky | Income shares | Schedule updated in recent sessions |
| Louisiana | Income shares | Combined adjusted gross income |
| Maine | Income shares | Uses gross income |
| Maryland | Income shares | Schedule extended to higher incomes |
| Massachusetts | Income shares variant | Own guideline worksheet, revised 2021 |
| Michigan | Income shares | Michigan Child Support Formula Manual |
| Minnesota | Income shares | Combined parental income for determining support |
| Mississippi | Percentage of income | 14/20/22/24/26 percent of adjusted gross |
| Missouri | Income shares | Form 14 |
| Montana | Melson formula | Own administrative rules version |
| Nebraska | Income shares | Net income basis |
| Nevada | Percentage of income | Tiered by income bracket since 2020 |
| New Hampshire | Income shares | Net income basis |
| New Jersey | Income shares | Appendix IX schedules |
| New Mexico | Income shares | Two worksheets by custody type |
| New York | Income shares | Percentages applied to combined income |
| North Carolina | Income shares | Three worksheets by custody type |
| North Dakota | Percentage of income | Applied to net income |
| Ohio | Income shares | Revised schedule effective 2019 |
| Oklahoma | Income shares | Combined gross monthly income |
| Oregon | Income shares | Includes parenting time credit |
| Pennsylvania | Income shares | Schedule updated for 2026 |
| Rhode Island | Income shares | Uses gross income |
| South Carolina | Income shares | Guidelines reviewed every four years |
| South Dakota | Income shares | Net income schedule |
| Tennessee | Income shares | Since 2005 |
| Texas | Percentage of income | Percentages of net resources, with a cap |
| Utah | Income shares | Separate tables by custody type |
| Vermont | Income shares | Available income basis |
| Virginia | Income shares | Va. Code 20-108.2 |
| Washington | Income shares | Economic table by child age |
| West Virginia | Income shares | Two worksheets |
| Wisconsin | Percentage of income | 17/25/29/31/34 percent of gross |
| Wyoming | Income shares | Net income schedule |
Percentage of Income States: The Actual Numbers
These six states publish a percentage you can apply directly. The figures below are for one, two, three, four, and five or more children.
| State | 1 child | 2 | 3 | 4 | 5+ | Applied to |
|---|
| Alaska | 20% | 27% | 33% | 36% | 40% | Adjusted annual income |
| Mississippi | 14% | 20% | 22% | 24% | 26% | Adjusted gross income |
| Nevada | 18% | 25% | 29% | 31% | 34% | Gross income, with bracket tiers |
| North Dakota | 14% | 20% | 22% | 24% | 27% | Net income |
| Texas | 20% | 25% | 30% | 35% | 40% | Monthly net resources |
| Wisconsin | 17% | 25% | 29% | 31% | 34% | Gross income |
Nevada applies these base percentages within income brackets, with lower percentages on income above certain thresholds, so a high earner does not pay a flat 18 percent of everything. Alaska applies the percentage to adjusted annual income under Civil Rule 90.3 and has separate rules for shared and divided custody.
Texas caps the income the percentages apply to. Effective September 1, 2025, the cap on monthly net resources under Texas Family Code 154.125 rose from $9,200 to $11,700, the largest single increase in state history. For one child, that moves the maximum guideline order from $1,840 per month to $2,340 per month. Orders finalized before that date stay under the old cap unless a parent asks the court to modify them and the court agrees.
Income Shares States Also Have Caps and Floors
Income shares states do not publish one clean percentage, because the amount changes with combined income. Two features matter most for families with lower or higher incomes.
Income caps. Most schedules stop at a maximum combined income, and above it the court has discretion. New York applies its percentages (17 percent for one child, 25 percent for two, 29 percent for three, 31 percent for four, and 35 percent for five or more) to combined parental income up to a cap that adjusts every two years. That cap is $193,000 effective March 1, 2026, through February 28, 2028, up from $183,000.
Self-support reserves. Nearly every state protects a paying parent's subsistence income. New York's 2026 self-support reserve is $21,546 per year, or $1,796 per month, equal to 135 percent of the federal poverty guideline for one person. If the standard calculation would push the paying parent below that line, the order is reduced. Other states use similar reserves tied to the poverty guidelines, which is why federal poverty level updates each January ripple into child support math.
Pennsylvania's 2026 schedule update raised basic obligations by roughly 3 to 10 percent across most income levels while keeping the same income shares structure. Connecticut's 2026 guidelines kept the model intact but raised the income ceiling, formalized support determinations for children with more than two legal parents, and tightened rules on imputed income and arrearages.
How to Estimate Your Own Number
- Identify your state's model using the table above. That tells you whose income matters.
- Gather income figures. Income shares and Melson states need both parents' gross monthly income. Percentage of income states need only the paying parent's. Include wages, self-employment income, bonuses, commissions, unemployment compensation, and in most states Social Security disability benefits paid to the parent.
- Apply the state's adjustments. Common deductions before the formula runs: federal and state taxes (in net income states), mandatory retirement contributions, union dues, health insurance premiums for the children, and support paid for other children under an existing order.
- Run the schedule or percentage. Percentage of income states are one multiplication. Income shares states require looking up the combined income on the state schedule, then multiplying by each parent's share of combined income.
- Add the extras. Most states add work-related childcare costs and the children's health insurance premium on top of the basic obligation, split in the same proportion.
- Apply custody and low-income adjustments. Shared parenting time reduces the order in most states once overnights cross a threshold, often 35 to 50 percent of nights.
- Check the state's official calculator. Nearly every state child support agency publishes one. Use it rather than a third-party estimator, and remember the output is a presumptive amount a judge can deviate from with written findings.
Child Support and Government Benefits
Child support and public benefits interact in ways that catch families off guard.
Child support you receive usually counts as income for SNAP. SNAP starts with gross monthly income and child support received is generally countable unearned income. That can push a household over the gross income test.
Child support you pay may be deductible for SNAP. Federal rules allow states to deduct legally obligated child support paid to someone outside the household, either as an income exclusion or a deduction. If you pay support and receive SNAP, report the order so the deduction is applied.
Child support does not count for Medicaid or ACA subsidies. Both use Modified Adjusted Gross Income, and child support received is not taxable income, so it stays out of the MAGI calculation. A parent receiving several hundred dollars a month in support can still qualify for Medicaid or premium tax credits based on wages alone.
TANF requires cooperation with child support enforcement. Households receiving TANF must open a child support case and cooperate with the state agency, and assign their support rights to the state while on assistance. Good cause exceptions exist in most states for domestic violence, conception by rape or incest, and pending adoption.
Nine states extend that cooperation requirement to SNAP. States may, but do not have to, require SNAP households to cooperate with child support enforcement. States using the option include Florida, Idaho, Kansas, Michigan, South Dakota, Arkansas, Nebraska, Mississippi, and Kentucky. In those states only the noncooperating individual can be disqualified, not the whole household.
Frequently Asked Questions
Which states use the income shares model?
Forty-one states plus the District of Columbia. The exceptions are the six percentage of income states (Alaska, Mississippi, Nevada, North Dakota, Texas, and Wisconsin) and the three Melson formula states (Delaware, Hawaii, and Montana). Illinois was the most recent large state to switch, moving from percentage of income to income shares on July 1, 2017, and Arkansas followed in 2020.
Does the custodial parent's income affect child support?
In income shares and Melson states, yes. Both parents' incomes go into the formula, and a higher-earning custodial parent generally lowers the other parent's obligation. In the six percentage of income states, the custodial parent's income is not part of the base calculation, though it can matter for deviations and for splitting childcare and medical costs.
What is the highest child support percentage by state?
Among states that publish a straight percentage, Alaska and Texas top out at 40 percent of income for five or more children. Alaska has the highest single-child percentage at 20 percent of adjusted income, tied with Texas at 20 percent of net resources. Comparing percentages across states is misleading, though, because each applies to a different income base (gross, net, or adjusted) and some cap the income the percentage applies to.
Is there a maximum child support amount?
Several states cap the income the guideline applies to. Texas caps monthly net resources at $11,700 as of September 1, 2025. New York applies its percentages to combined parental income up to $193,000 for 2026 through February 2028. Above those thresholds, a judge decides whether more support is appropriate based on the children's needs and the parents' circumstances.
Can child support be changed if my income drops?
Yes, through a modification request filed with the court or the state child support agency. Most states allow a review when there is a substantial change in circumstances, often defined as a change that would move the order by 15 to 20 percent or a fixed dollar amount. Support does not adjust automatically when you lose a job, and arrears keep building until a modification is granted, so file quickly rather than waiting.
Does receiving child support disqualify me from SNAP or Medicaid?
It can affect SNAP, because child support received counts toward the gross income test in most states. It does not affect Medicaid or ACA marketplace subsidies, which use Modified Adjusted Gross Income and exclude child support. A household over the SNAP limit on paper may still qualify for Medicaid, WIC, childcare assistance, and reduced-price school meals.
How do I find my state's official calculator?
Every state child support agency publishes guidelines and most publish a calculator or worksheet on the agency website. Search for your state name plus "child support guidelines worksheet." Use the official state tool rather than a commercial calculator, and treat the result as a presumptive amount a judge can adjust.
