California Child Support Guide: How Payments Are Calculated

California uses a statewide guideline formula to calculate child support. This guide explains how the formula works, what factors affect your payment, and how to request a modification.

The California Child Support Guideline

The child support guideline is established in California Family Code §4055. The formula is designed so that children receive the same proportion of parental income they would have if their parents lived together.

The Basic Formula

In simple terms, California child support is calculated as follows:

Each parent’s income is shared proportionally based on how much time each parent spends with the child and how much each parent earns.

Key Inputs to the Formula

Input	Description
Monthly Net Income (Parent 1)	After taxes, deductions, and mandatory retirement
Monthly Net Income (Parent 2)	Same calculation for the other parent
Timeshare Percentage	Percentage of time each parent has physical custody
Health Insurance Premium	Cost of the child’s health insurance
Childcare Costs	Work-related or education-related childcare
Other Children	Support obligations for children from other relationships
Tax Filing Status	Head of household vs. single

Understanding Net Income

California defines net income broadly. It includes:

• Wages and salary
• Self-employment income
• Bonuses and commissions
• Rental income
• Investment income
• Unemployment benefits
• Disability benefits
• Pensions and retirement income

Certain deductions are allowed:

• Federal and state income taxes
• Social Security and Medicare
• Mandatory retirement contributions
• Union dues
• Health insurance premiums (for yourself, not the child)

Important: The court can impute income if it finds a parent is voluntarily unemployed or underemployed. This means the court may calculate support based on what you could earn rather than what you do earn.

Timeshare and Custody

The amount of time each parent spends with the child significantly affects the calculation:

• 50/50 Custody: Both parents have substantial shared custody. Support payments are typically lower.
• Sole or Primary Custody: The custodial parent receives support from the non-custodial parent.
• Visitation Only: The non-custodial parent’s timeshare is limited, resulting in higher support.

The “High-Income” Exception

When the combined monthly net income of both parents exceeds $10,000 (as of 2026), the court has discretion to depart from the guideline formula. This does not mean support is capped — the court may order an amount based on the child’s needs and the parents’ station in life.

Additional Expenses

Beyond the base formula, child support orders typically include:

Mandatory Add-Ons

• Childcare: Paid directly or added to the support order
• Health Insurance: The cost of covering the child
• Uninsured Medical Expenses: Typically split proportionally

Discretionary Add-Ons

• Education Expenses: Private school tuition
• Extracurricular Activities: Sports, music lessons, etc.

How to Estimate Your Payment

You can use our California Child Support Calculator to estimate your monthly payment. The calculator follows the same guideline formula used by California courts.

Modifying Child Support

Child support orders can be modified when there is a significant change in circumstances:

• Loss or change of job
• Change in custody time
• Change in childcare costs
• Child reaching age of majority (18) or graduating high school (19)
• Change in a parent’s income

To request a modification, file Request for Order (FL-300) with the court. If you receive CalWORKs, the Department of Child Support Services can review your case every 3 years.

Duration of Child Support

In California, child support generally continues until:

• The child turns 18 (or 19 if still in high school full-time)
• The child is emancipated
• The child marries or joins the military

The court can order support for a child over 18 who is incapacitated from supporting themselves.

Frequently Asked Questions

Can parents agree to a different amount?

Yes. Parents can agree to a child support amount different from the guideline, if:

• Both parents sign a Stipulation (FL-350)
• The agreement is in the child’s best interest
• Each parent understands their guideline rights

The court must approve any agreement that deviates from the guideline.

What if the other parent hides income?

If you believe the other parent is hiding income, you can:

1. Request financial discovery (bank statements, tax returns)
2. File a motion to compel disclosure
3. Ask the court to impute income based on earning capacity

Does child support cover college expenses?

No. California child support does not include college expenses. Parents can agree to pay for college, and in some cases, the court can order support for a child over 18 in exceptional circumstances.

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Next Step: Use our Child Support Calculator to estimate your monthly payment under California law.