Estimate child support payments using your state's official formula. Covers Income Shares (40 states), Percentage of Income (6 states), and the Melson Formula (3 states). Select your state for an instant calculation.
The average child support payment in the US is approximately $400/month (Census Bureau). In Income Shares states (40 states), both parents' incomes determine the obligation. In Percentage of Income states (Texas, Wisconsin, Mississippi, Alaska, Nevada, North Dakota), only the paying parent's income matters. Texas applies 20% for one child, Wisconsin 17%, Mississippi 14%. Delaware, Hawaii, and Montana use the Melson Formula, which first reserves a subsistence allowance. Use the calculator below for your state's amount.
Child support in the United States is calculated using one of three models, depending on the state. The most common is the Income Shares model, used by 40 states. This approach combines both parents' gross incomes and references a schedule that estimates what the family would have spent on the children if the household remained intact. The total obligation is then divided proportionally between the parents based on their individual incomes.
Custody arrangements directly affect the child support amount. In sole custody situations, the non-custodial parent pays the full calculated share. Shared custody (92 to 128 overnights) typically reduces the obligation by approximately 25%, reflecting the increased direct spending by the non-custodial parent. Equal custody (129 to 182 overnights) can reduce the amount by roughly 40%. Courts may also adjust for health insurance premiums and childcare expenses paid by either parent.
Source: LegalCost.us Child Support Calculator, data verified against official state statutes, updated July 2026.
These calculators provide educational estimates only. Child support determinations involve many factors not captured here, including special needs, extraordinary expenses, and existing support obligations. Always consult a licensed family law attorney in your state before making legal decisions.
Courts define income more broadly than most parents expect. The figure that goes into the calculation above is rarely the same as take-home pay, and knowing the difference changes what you should expect at a hearing.
The logic behind the exclusions is that benefits designed to meet one household's subsistence needs should not be redirected to another.
Most states start from gross income before taxes. A minority use net income after specified deductions. Texas is the clearest example of the second group: net resources means gross income minus federal income tax at the single rate, Social Security and Medicare, union dues, and the cost of the child's health and dental insurance. Voluntary retirement contributions and car payments are not deductible there.
Courts do not simply accept the bottom line on a tax return. Expenses that reduce taxable income are frequently added back for support purposes when they carry a personal benefit. A vehicle, a home office, or a phone plan run through a business may be treated as income by a family court judge even though the IRS accepted the deduction. Courts also tend to average two or three years of returns rather than relying on a single year.
If a parent is voluntarily unemployed or working below their demonstrated capacity, most states calculate support on what that parent could reasonably earn rather than what they actually report. Reducing your hours shortly before a hearing rarely produces the intended result.
The guideline formula produces a base obligation. Several costs are then added separately and split between the parents in proportion to income, which means the final order is usually higher than the base figure alone.
| Add-on | How it is handled |
|---|---|
| Child's health insurance premium | Added to the base and divided proportionally by income. In some states it is folded into the schedule instead. |
| Work-related childcare | Added and divided proportionally. Must be necessary for a parent to work or attend school. |
| Extraordinary medical expenses | Uninsured costs above a stated threshold, shared in the same proportion. |
| Children from other relationships | Most states allow a deduction or credit. Some subtract an existing order from income before calculating the new one. Others apply a multiple-family adjustment inside the guideline. |
| Income caps | Nearly every state caps the income to which guideline percentages apply. Above the cap, the court needs evidence of the child's actual needs to order more. |
| Minimum obligation | Most states set a floor so an order exists even when the paying parent reports no income. |
Texas illustrates both the cap and the floor. As of 1 September 2025 the net resources cap rose from $9,200 to $11,700 per month, the first adjustment since 2019. That puts maximum guideline support at $2,340 for one child, $2,925 for two, and $3,510 for three. At the other end, an obligor with no reported income still owes a minimum of $200 per month.
One point about scaling that surprises people: support rises with each additional child, but not proportionally. Guidelines account for economies of scale in a household, so two children typically cost around one and a half times what one child costs, not double. The Texas percentages show this clearly, rising from 20 percent for one child to 25 for two and 30 for three.
Sources: Texas Family Code sections 154.062, 154.068 and 154.125, National Conference of State Legislatures guideline surveys, state child support agency publications. Updated July 2026.
A child support order is not permanent, but it does not adjust on its own either. Either parent can petition to modify it, and the standard is a substantial change in circumstances.
A significant income change for either parent, commonly defined as 10 to 20 percent or a specific dollar threshold depending on the state. A change in the custody arrangement. A child aging out or becoming emancipated. A major shift in medical or insurance costs. Many states also permit a routine review every three years without requiring proof that anything changed.
Parents who agree privately to reduce payments create arrears, not a modification. The existing order stays enforceable until a court issues a new one.
Not from the date your circumstances changed. This is the most expensive and most avoidable mistake in child support administration. A parent who loses their job in January and files in June owes the full amount for those five months, with no retroactive adjustment.