How is child support calculated in California?

California uses a statewide uniform guideline formula (Family Code 4055) based on the net disposable income of both parents and the amount of time each parent spends with the child.

What is the 'K factor' in child support?

The K factor is part of the California formula representing the percentage of income to be allocated for child support, which varies based on total income and number of children.

Does shared custody lower child support payments in CA?

Yes. In California, the 'H%' (percentage of time the high earner has primary physical responsibility for the children) is a key variable. Generally, the more time the paying parent spends with the child, the lower the support obligation.

California Child Support Calculator

Use our free California Child Support Calculator to estimate monthly payments. This tool uses the Statewide Uniform Guideline formula (California Family Code § 4055) based on gross income, custody time share, and number of children.

Parent A Gross IncomeParent B Gross IncomeIncome FrequencyNumber of ChildrenHigh Earner's Parenting Time (%)

30%

Enter the percentage of time the higher-earning parent spends with the child.

Estimated Monthly Support

*Estimate only. Courts may adjust for health insurance, mandatory retirement, union dues, and hardship deductions.

Official CA.gov Calculator CA Courts Self-Help

How to Use This Calculator

Enter Gross Income: Input the total pre-tax income for both parents. This includes wages, bonuses, commissions, and self-employment income.
Select Frequency: Choose how often you are paid (e.g., Monthly, Bi-weekly) to ensure accurate annual calculations.
Adjust Parenting Time: Slide the bar to reflect the percentage of time the higher-earning parent spends with the child. This is known as the "Time Share" or H% factor.
Review Estimate: The calculator immediately updates the estimated obligation based on California Family Code guidelines.

Understanding the California Formula

California uses a complex algebraic formula (Family Code § 4055) to determine child support. The basic formula is:

CS = K (HN - (H%) (TN))

CS: Child Support Amount
K: Amount of income to be allocated for child support (The "K-Factor")
HN: High Net (Disposable income of the high earner)
H%: Approximate percentage of time the high earner has physical custody
TN: Total Net (Combined disposable income of both parents)

Frequently Asked Questions

What counts as "Gross Income" in California?

Gross income includes income from all sources, such as salaries, commissions, bonuses, dividends, pensions, interest, trust income, annuities, workers’ compensation benefits, unemployment insurance benefits, disability insurance benefits, and spousal support received from a person not a party to the proceeding.

How does 50/50 custody affect payments?

In a true 50/50 shared custody arrangement, child support is typically lower than in sole custody situations. However, even with 50/50 custody, if there is a significant disparity in income between parents, the higher earner will likely still pay support to the lower earner to maintain a similar standard of living in both homes.

What deductions are allowed from Gross Income?

To arrive at "Net Disposable Income," courts deduct state and federal income taxes, FICA (Social Security), mandatory union dues, mandatory retirement contributions, health insurance premiums for the parent and children, and support paid for other children from different relationships.