Family Court Playbook · Step 6 of 12
How Child Support is Calculated in California
Understanding the guideline formula, income factors, and how timeshare affects your amount
What is guideline child support?
California uses a mathematical formula (Family Code § 4055) to calculate child support. The formula considers both parents' income, the percentage of time each parent has custody, tax filing status, and certain deductions. The result is called “guideline” support.
How the formula works
The formula: CS = K[HN − (H%)(TN)]. K is the amount of both parents' income allocated for child support. HN is the high earner's net monthly disposable income. H% is the approximate percentage of time the high earner has the children. TN is the total net monthly disposable income of both parents. The court almost always orders guideline unless there is a reason to deviate.
The guideline formula
Income and timeshare determine the amount
Guideline Calculator
What affects the amount
Income of both parents (gross and net), percentage of time with each parent (timeshare), tax filing status, health insurance costs for children, childcare costs, and other children from other relationships all factor into the calculation.
Try the calculator
How to modify an existing order
If circumstances have changed (job loss, raise, change in timeshare), you can file an RFO to modify support. The court looks at current income, not what was true when the original order was made.
Judicial discretion
Calculate yours
Use our free California guideline calculator to estimate your child support amount.
Open the free calculatorA family law attorney will always have the biggest impact on your case. If you can afford one, we encourage you to hire one.