California child support calculator

How does California calculate child support?

California uses its own formula, not a flat percentage of the paying parent’s wages: CS = K[HN − (H% × TN)] (§4055). This page uses the edition effective September 1, 2024, confirmed against the official text on October 15, 2026.

CS is child support; HN is the higher earner’s net monthly disposable income; TN is both parents’ combined net monthly disposable income (§4055). Net income accounts for federal and state taxes, and §4055 directs the calculation of net disposable income to §4059. K is the allocation factor, combining an income-band fraction below with a parenting-time multiplier (§4055).

A positive result means the higher earner pays the lower earner; a negative result means the lower earner pays the absolute amount to the higher earner (§4055). For two children, the formula amount is multiplied by 1.6; for three, by 2 (§4055). The line-by-line worksheet shows the estimate, while the common-income table illustrates how results vary.

• Combined net income of $0–$2,900 a month: the income-band fraction is 0.165 + TN/82,857 (§4055).
• $2,901–$5,000 a month: 0.131 + TN/42,149 (§4055).
• $5,001–$10,000 a month: 0.250 (§4055).
• $10,001–$15,000 a month: 0.10 + 1,499/TN (§4055).
• Over $15,000 a month: 0.12 + 1,200/TN, so the formula continues above that income level (§4055).

How does parenting time affect support?

Parenting time is part of the formula itself, not a separate overnight discount. H% represents the approximate share of time the higher earner has primary physical responsibility for the children; different arrangements for different children are averaged (§4055).

At or below 50%, the parenting-time multiplier used in K is one plus H%; above 50%, it is two minus H% (§4055). H% also appears directly in the support formula. Equal parenting time therefore does not automatically mean no support, because the parents’ net incomes also matter.

What else changes the support amount?

The base formula is not always the complete amount. California law requires certain additional costs and allows others, while a low-income adjustment can reduce the formula result.

• Child care: actually incurred costs related to employment or reasonably necessary employment education or training must be added unless already included in the guideline calculation (§4062).
• Uninsured health care: reasonable costs for the children must be added (§4062).
• Special needs: the court may add costs related to educational or other special needs (§4062).
• Parenting-time travel: the court may add travel expenses for visitation (§4062).
• Low income: the parent who pays may qualify for an adjustment when net monthly disposable income is below monthly gross earnings from full-time California minimum-wage work. The statutory benchmark uses 40 hours a week and 52 weeks a year (§4055).

When does support end or change?

Support continues after age 18 for an unmarried child who is not self-supporting and attends high school full time, until completion of the 12th grade or age 19, whichever comes first (§3901). A physician-documented medical condition preventing full-time attendance excuses that attendance requirement. Parents may also agree to provide additional support (§3901).

A new calculator estimate does not itself change an existing order. The California Department of Child Support Services or a court self-help center can explain the process for requesting a review.

For an official calculation, the California Department of Child Support Services provides the California Child Support Guideline Calculator and its user guide. The agency explains that the calculator follows the same legal guidelines used in California courts, but its result is an estimate of what may be ordered.