Child Support as a Percentage of Income: Complete 50-State Guide

Overview: Two Models for Calculating Child Support

When people ask "what percentage of income goes to child support," the answer depends entirely on which state you live in. The United States uses two primary models for calculating child support: the Percentage of Income model and the Income Shares model. Understanding which model your state uses is the first step to understanding your child support obligation.

The Percentage of Income Model

Under this model, child support is calculated as a flat percentage of the non-custodial parent's income. The percentage is determined by the number of children: one child gets a lower percentage, while five or more children get the highest. This model is simple and predictable but does not account for the custodial parent's income. Only a handful of states use this approach.

The Income Shares Model

Under this model, the court estimates the total amount that would have been spent on the child if the parents had stayed together. This total is then divided between the parents proportionally based on their respective incomes. The parent with the higher income pays a larger share. This model is used by approximately 40 states and the District of Columbia and is considered the more equitable approach because it accounts for both parents' financial situations.

There is also a third model called the Melson Formula, used by Delaware, Hawaii, and West Virginia. The Melson formula is a variation of the income shares model that first ensures each parent retains a minimum self-support amount before calculating support. It then allocates additional income to the child's primary needs and, finally, to supplemental needs to improve the child's standard of living.

Flat Percentage States: Exact Rates by Number of Children

Only five states use the flat percentage of income model. Here are the exact rates for each:

Texas

Texas is the most well-known percentage state and applies the following percentages to the non-custodial parent's net income (income after taxes and certain deductions):

• 1 child: 20% of net income
• 2 children: 25% of net income
• 3 children: 30% of net income
• 4 children: 35% of net income
• 5 children: 40% of net income
• 6+ children: Not less than 40% of net income

Texas caps the net income subject to these percentages at a statutory amount, which is adjusted periodically. For income above this cap, the court has discretion to apply additional percentages based on the child's needs and the parents' circumstances. Texas also applies a self-support reserve, ensuring the paying parent retains at least a minimum amount for their own living expenses.

Alaska

Alaska uses a percentage model adjusted for custody time. The base percentages for sole custody are:

• 1 child: 20% of net income
• 2 children: 27% of net income
• 3 children: 33% of net income
• 4 children: 39% of net income

Alaska adjusts these percentages based on the number of overnight visits the non-custodial parent has with the child.

Mississippi

Mississippi applies the following percentages to the non-custodial parent's adjusted gross income:

• 1 child: 14% of adjusted gross income
• 2 children: 20% of adjusted gross income
• 3 children: 22% of adjusted gross income
• 4 children: 24% of adjusted gross income
• 5+ children: 26% of adjusted gross income

Mississippi courts may deviate from these percentages based on specific circumstances, and the percentages may be adjusted for shared custody arrangements.

North Dakota

North Dakota calculates child support based on a percentage of the obligor's net income, using a sliding scale that varies with income level and the number of children. The percentages generally fall in the following ranges:

• 1 child: approximately 17-20% of net income
• 2 children: approximately 25-29% of net income
• 3 children: approximately 29-34% of net income
• 4 children: approximately 33-38% of net income
• 5+ children: approximately 36-41% of net income

North Dakota also considers the custodial parent's income for certain adjustments and uses a self-support reserve to protect low-income obligors.

Wisconsin

Wisconsin uses a percentage standard based on the non-custodial parent's gross income:

• 1 child: 17% of gross income
• 2 children: 25% of gross income
• 3 children: 29% of gross income
• 4 children: 31% of gross income
• 5+ children: 34% of gross income

Wisconsin adjusts these percentages for shared placement cases where the child spends more than 25% of overnights (at least 92 overnights per year) with each parent. In shared placement cases, the court calculates support based on both parents' incomes and the proportionate time the child spends with each parent.

The Income Shares Model: How It Works

The income shares model does not use a single fixed percentage. Instead, it works through a multi-step calculation:

1. Determine each parent's gross income: The court calculates both parents' incomes from all sources, including wages, salaries, bonuses, commissions, self-employment income, investment income, and other sources.
2. Calculate combined income: Both parents' incomes are added together to determine the total household income available for the child.
3. Consult the state's support schedule: Each state publishes a table (sometimes called a schedule or grid) that shows the presumed total support amount based on combined income and the number of children. This table is based on economic data about what parents actually spend on their children at different income levels.
4. Allocate the support proportionally: Each parent's share of the total support amount is based on their proportion of the combined income. If Parent A earns 60% of the combined income, Parent A is responsible for 60% of the total support amount.
5. Adjust for custody time and expenses: The court adjusts the base amount for health insurance, childcare costs, extraordinary medical expenses, and the amount of time the child spends with each parent.

Example Calculation

Consider a case in an income shares state where Parent A earns $5,000 per month and Parent B earns $3,000 per month, for a combined income of $8,000 per month. They have two children.

Based on the state's support schedule, the total monthly support obligation for two children at $8,000 combined monthly income might be approximately $1,600 to $1,800 (this varies by state).

Parent A earns 62.5% of the combined income ($5,000 / $8,000), so Parent A is responsible for 62.5% of the support amount. Parent B earns 37.5%, so Parent B is responsible for 37.5%.

If the children live primarily with Parent B, Parent A pays their share to Parent B. So Parent A would pay approximately $1,000 to $1,125 per month. This equates to roughly 20-22% of Parent A's gross income — but this percentage is a result of the calculation, not a fixed rate.

Use our child support calculator to run numbers specific to your situation and state.

How Percentages Change with Custody Arrangements

The amount of time the child spends with each parent significantly affects the child support calculation, regardless of which model the state uses.

Sole Physical Custody

When one parent has sole physical custody (the child lives with them the vast majority of the time), the standard child support percentage or formula applies without significant adjustments. The non-custodial parent pays the full guideline amount to the custodial parent.

Joint or Shared Physical Custody

When parents share physical custody, most states reduce the child support amount because both parents are directly providing for the child during their respective parenting time. The exact adjustment varies:

• Texas: Reduces the applicable percentage based on the number of overnight stays. If the non-custodial parent has the child 20-29% of the time, the percentage is reduced; at 30% or more, the reduction is more significant.
• California:Uses a "time-share" adjustment where the support amount decreases proportionally as the non-custodial parent's time with the child increases.
• Florida: Reduces the support obligation based on the number of overnight stays. The state uses a "substantial time-sharing" adjustment for parents who have the child 20% or more of the overnights.
• Illinois: The income shares model inherently accounts for shared parenting time by offsetting each parent's direct expenses during their parenting time.

Split Custody

When parents split custody of multiple children (for example, each parent has primary custody of one child), the support calculation becomes a cross-calculation. Each parent owes support for the child living with the other parent, and the obligations are offset against each other. The parent with the higher obligation pays the difference.

Self-Support Reserves

Most states include a self-support reserve in their child support calculations. This is a minimum amount of income that the paying parent is allowed to retain for their own basic living expenses. The purpose is to prevent the paying parent from being driven into poverty by child support obligations.

The self-support reserve is typically set at or near the federal poverty level for a single individual. In 2024, this amount is approximately $14,580 per year, or about $1,215 per month. If the paying parent's income is at or near this level, the child support obligation is reduced or capped to ensure they retain enough to survive.

Some states have additional protections for low-income parents:

• Minimum support orders: Many states set a minimum child support amount (often $50-$100 per month) even for very low-income parents.
• Income thresholds: Some states have income thresholds below which the standard formula does not apply, and the court determines a nominal or reduced amount.
• Graduated scales: Some states use a graduated scale where low-income parents pay a reduced percentage of their income.

Comparison: All 50 States

The following table summarizes the child support calculation model used by each state and the approximate percentage range for one child. These percentages are approximate and will vary based on income level, custody arrangement, and other factors.

Percentage of Income States

• Alaska — Percentage model — 20% for 1 child (net income)
• Mississippi — Percentage model — 14% for 1 child (adjusted gross)
• North Dakota — Percentage model (sliding scale) — 17-20% for 1 child (net income)
• Texas — Percentage model — 20% for 1 child (net income)
• Wisconsin — Percentage model — 17% for 1 child (gross income)

Melson Formula States

• Delaware — Melson formula — varies based on income levels and primary/supplemental needs
• Hawaii — Melson formula — varies based on income levels
• West Virginia — Melson formula — varies based on income levels

Income Shares States

The following states use the income shares model. The effective percentage for the paying parent depends on both parents' incomes and cannot be expressed as a single fixed rate. The approximate range for a typical case (where the paying parent earns roughly twice what the receiving parent earns) is 15-25% for one child:

• Alabama — Income shares
• Arizona — Income shares
• Arkansas — Income shares
• California — Income shares
• Colorado — Income shares
• Connecticut — Income shares
• District of Columbia — Income shares
• Florida — Income shares
• Georgia — Income shares
• Idaho — Income shares
• Illinois — Income shares
• Indiana — Income shares
• Iowa — Income shares
• Kansas — Income shares
• Kentucky — Income shares
• Louisiana — Income shares
• Maine — Income shares
• Maryland — Income shares
• Massachusetts — Income shares
• Michigan — Income shares
• Minnesota — Income shares
• Missouri — Income shares
• Montana — Income shares
• Nebraska — Income shares
• Nevada — Income shares
• New Hampshire — Income shares
• New Jersey — Income shares
• New Mexico — Income shares
• New York — Income shares
• North Carolina — Income shares
• Ohio — Income shares
• Oklahoma — Income shares
• Oregon — Income shares
• Pennsylvania — Income shares
• Rhode Island — Income shares
• South Carolina — Income shares
• South Dakota — Income shares
• Tennessee — Income shares
• Utah — Income shares
• Vermont — Income shares
• Virginia — Income shares
• Washington — Income shares
• Wyoming — Income shares

For specific calculations based on your income, your co-parent's income, and your state's formula, use our child support calculator. You can also learn more about the factors that go into the calculation in our article on what child support is based on or explore typical payment amounts in our guide to the average child support payment.