How is child support calculated in California?

California uses an algebraic formula: CS = K × [HN - (H% × TN)]. This considers both parents' net disposable incomes and the percentage of time each parent has custody. K is a factor based on combined income, HN is the higher earner's net income, H% is their time-share, and TN is total combined income.

Does custody time affect child support in California?

Yes, significantly. California's formula directly incorporates each parent's percentage of custodial time. The more time the higher-earning parent has with the children, the less support they typically pay, because they're directly providing for the children during that time.

California Child Support Calculator 2025 | Free & Private

How California Calculates Child Support

California uses a unique algebraic formula that considers both parents' incomes and the amount of time each parent spends with the children. Unlike percentage-based states, California calculates support based on income differential and custody time.

CS = K × [HN - (H% × TN)]

Where K is a factor based on income, HN is the higher earner's net income, H% is their time-share percentage, and TN is total combined net income.

Parent 1 - Monthly Income

Gross Monthly Income

Monthly Tax Deductions

Federal, state, FICA taxes

Health Insurance (for self)

Mandatory Retirement

Parent 1 Net Disposable Income $0

Parent 2 - Monthly Income

Gross Monthly Income

Monthly Tax Deductions

Federal, state, FICA taxes

Health Insurance (for self)

Mandatory Retirement

Parent 2 Net Disposable Income $0

Custody Time-Share

Enter the percentage of time each parent has physical custody. Must total 100%.

Parent 1 Time-Share

Parent 2 Time-Share

Children & Add-On Expenses

Number of Children

Monthly Childcare Costs

Work-related childcare expenses

Children's Health Insurance

Uninsured Health Costs

Average monthly out-of-pocket medical

Results

Guideline Child Support

Monthly Child Support $0

Annual Amount $0

Payor -

Combined Net Income $0

Add-On Share (childcare, health) $0

Important Disclaimer

This calculator provides estimates only based on California Family Code Section 4055 guidelines. California's actual formula is complex with additional factors. Actual court-ordered amounts may differ based on judicial discretion, hardship deductions, and specific circumstances. This calculator does not constitute legal advice. For accurate calculations, use the official California calculator or consult a family law attorney.