Percentage of Income Calculator - Child Support in TX, WI & More
The percentage of income model is the simplest child support calculation method, applying a fixed percentage to the noncustodial parent's income based on the number of children. While only a handful of states use this model as their primary method, it is important to understand how it works, especially in major states like Texas and Wisconsin.
How the Percentage of Income Model Works
Unlike the income shares model, which considers both parents' incomes, the percentage of income model considers only the noncustodial parent's income. A predetermined percentage is applied based on the number of children to determine the support amount. This makes it simpler to calculate but potentially less equitable because it ignores the custodial parent's income.
There are two variations of the percentage of income model:
Flat Percentage Model
In the flat percentage model, the same percentage applies regardless of income level. This is the simpler version and is used by Texas and Wisconsin. For example, in Texas:
Texas Child Support Percentages
| Number of Children | Percentage of Net Resources |
|---|---|
| 1 child | 20% |
| 2 children | 25% |
| 3 children | 30% |
| 4 children | 35% |
| 5+ children | 40% (minimum) |
Texas calculates support on "net resources" -- gross income minus federal taxes, Social Security, Medicare, state income taxes, union dues, and health insurance for the child. Texas caps the income subject to these percentages (in 2025, the cap applies to net resources over approximately $9,200/month).
Varying Percentage Model
In the varying percentage model, the percentage changes based on the income level. Higher incomes may have lower percentages applied, reflecting the principle that the percentage of income spent on children decreases as income increases. This model is less common.
Texas: Detailed Breakdown
Texas uses the flat percentage model applied to the noncustodial parent's "net resources." Understanding how Texas calculates net resources is critical:
What Counts as Income (Gross Resources)
- Wages, salary, commissions, tips, overtime, and bonuses
- Self-employment income
- Interest, dividends, and royalties
- Rental income
- Retirement and pension income
- Trust income
- Social Security benefits (other than SSI)
- Unemployment benefits
- Workers' compensation
- Capital gains
- Gifts and prizes (in some circumstances)
What Is Deducted (To Get Net Resources)
- Federal income taxes (based on filing single with one personal exemption)
- Social Security taxes
- Medicare taxes
- State income taxes (not applicable in Texas, which has no state income tax)
- Union dues
- Health insurance premiums for the child
The Texas Income Cap
Texas caps the amount of net resources subject to the guideline percentages. For 2025, the cap is approximately $9,200 per month in net resources. For income above the cap, the court has discretion to order additional support based on the proven needs of the child. This means that for very high-income earners, the guideline percentage applies only to the first $9,200 in net resources, and additional support requires proving the child's needs exceed the guideline amount.
Wisconsin's Approach
Wisconsin also uses a percentage of income model, but with some differences from Texas:
- 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 calculates support on gross income rather than net resources, which is a significant difference from Texas. Wisconsin also has provisions for shared placement (when the child spends at least 92 overnights per year with each parent), which uses a modified calculation considering both parents' incomes and the time split.
Comparison: Percentage of Income vs. Income Shares
- Simplicity: The percentage model is simpler to calculate -- only one parent's income is needed. The income shares model requires both parents' incomes and reference to a detailed table.
- Equity: The income shares model is generally considered more equitable because it considers both parents' financial capacity. The percentage model can result in disproportionate outcomes when the custodial parent earns significantly more or less than the noncustodial parent.
- Custody time: The income shares model typically has built-in adjustments for shared custody. The percentage model may require separate provisions or judicial discretion to account for significant parenting time.
- Predictability: The percentage model is more predictable -- if you know the income, you know the support. The income shares model involves more variables and judgment calls.
Deviation from Guidelines
Even in percentage-of-income states, courts can deviate from the guideline amount when the result would be unjust. In Texas, the court can consider factors such as the child's age and needs, the ability of the parents to contribute to the child's support, financial resources available for support, the amount of possession and access time, child-related expenses (travel, healthcare, education), and provisions for healthcare coverage.
Frequently Asked Questions
How does the percentage of income model work?
The percentage of income model calculates child support by applying a fixed percentage to the noncustodial parent's income based on the number of children. In Texas, the percentages are 20% for 1 child, 25% for 2 children, 30% for 3 children, 35% for 4, and 40% for 5+. Only the noncustodial parent's income is considered, making it simpler but potentially less equitable than the income shares model used in most states.
Which states use the percentage of income model?
A small number of states use the percentage of income model as their primary child support calculation method. Texas and Wisconsin are the most well-known. Alaska, Mississippi, Nevada, and North Dakota also use variations of this model. The remaining 41 states use the income shares model, which considers both parents' incomes. Three states (Delaware, Hawaii, Montana) use the Melson Formula, which is a modified income shares approach.
Is the percentage of income model fair?
The fairness of the percentage model is debated. Supporters argue it is simple, transparent, and predictable. Critics argue it can produce unfair results because it ignores the custodial parent's income -- a high-earning custodial parent receives the same support amount as a low-earning one. It also does not automatically account for significant parenting time by the noncustodial parent. Most child support policy experts favor the income shares model as more equitable.
What is the income cap in Texas child support?
Texas caps the net resources subject to the guideline percentages at approximately $9,200 per month (this amount is adjusted periodically). For income above the cap, the guideline percentage does not automatically apply. Instead, the custodial parent must prove the child's needs exceed the guideline amount to obtain additional support. Courts can order above-guideline support based on the child's actual expenses, lifestyle, and needs.