California Child Support Calculator

How California's Guideline Formula Works

In California, your child support is determined by a complex statewide formula found in California Family Code § 4055. This calculation primarily considers both your and the other parent's net income and the exact percentage of time you each physically care for your child.

What Does Child Support Cover in CA?

California's child support calculation is directly impacted by the percentage of time each parent has physical custody. Governed by Family Code § 4055, the formula does not have a specific overnight threshold for a shared custody adjustment; instead, every increase in parenting time continuously adjusts the support amount, with approximately equal (50/50) time often resulting in the lowest support order.

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✓ Verified for 2026 Guidelines • Reviewed October 2026 by Harmoney

California Child Support Guidelines at a Glance

Guideline Model Income Shares Model
Governing Legal Authority California Family Code § 4055
Shared Custody Threshold Substantial Equal Time
Age Support Ends Age 18 (or 19 if in High School)
Modification Standard Substantial Change in Circumstances

California Child Support FAQs


At what age does child support end in CA?

In California, child support typically ends when a child turns 18, but it continues until age 19 if the child is unmarried and still attending high school full-time. This rule is established under California Family Code § 3901. Parents can mutually agree in writing to extend support beyond this, but a court cannot order it.

How is child support calculated if one parent is unemployed in CA?

If a parent is unemployed or underemployed, a California court can impute income to them based on their earning capacity, considering their skills, qualifications, and job opportunities. Under California Family Code § 4058(b), this is done to ensure the parent is contributing to their child's needs to the best of their ability and not intentionally avoiding their support obligation.

How do I modify a child support order in CA?

To modify a child support order in California, you must file a motion and prove there has been a 'significant change in circumstances' since the last order was made. As outlined in California Family Code § 3651, this can include a significant increase or decrease in either parent's income, a change in the custody schedule, or a change in a child's needs.

Does CA child support cover college expenses?

No, California courts cannot order a parent to pay for college expenses, as the legal duty to support a child ends at age 18, or 19 if still in high school. However, parents can voluntarily create a legally binding written agreement to share college costs, which a court can then enforce.

How does CA handle health insurance and childcare costs?

In California, costs for a child's health insurance and necessary work-related childcare are treated as mandatory add-ons and are typically ordered to be shared equally (50/50) between the parents. These expenses, governed by California Family Code § 4062, are calculated on top of the base guideline child support amount.