California Child Support Calculator

California uses a statewide algebraic formula, not an income-shares schedule, under Cal. Fam. Code § 4055: CS = K[HN - (H%)(TN)]. HN is the higher earner's net monthly disposable income, TN is the parents' combined net monthly disposable income, H% is the approximate percentage of time the higher earner has primary physical responsibility for the children, and K is a factor (based on H% and an income band) representing the share of income allocated to support. The one-child result is multiplied by a statutory factor (1.6 for two children, 2.0 for three, and so on). California revised this formula effective September 1, 2024 under SB 343, including updated K-factor income bands tied to minimum wage.

California's § 4055 formula uses each parent's NET monthly disposable income, not gross. Gross income (per § 4058) includes wages, salaries, commissions, bonuses, self-employment income, dividends, interest, pensions, Social Security, unemployment, disability, workers' compensation, and spousal support received. Net disposable income (per § 4059) is gross income minus federal and state income tax, FICA (Social Security and Medicare), mandatory union dues and retirement contributions, health insurance premiums, any existing child or spousal support being paid, and certain hardship deductions. This calculator asks you to enter net disposable income directly. California courts may also impute income to a parent who is voluntarily unemployed or underemployed.

Parenting time is built directly into California's formula as H%, the approximate percentage of time the higher earner has primary physical responsibility for the children. It appears in the (H%)(TN) term and also sets the K base multiplier (1 + H% when H% is 50% or less, 2 - H% when it is more). Because H% is a continuous variable rather than a set of day thresholds, every additional day of parenting time the higher earner has gradually reduces the guideline support they pay. There is no fixed '100-day' or '116-day' cliff in the statute.

Yes, either parent can request a modification when there has been a significant change in circumstances. Because California support is set by the statewide § 4055 formula, the order is recalculated when the inputs change. Common reasons include significant changes in either parent's net income, changes in the parenting time each parent has (which changes H%), changes in childcare or medical costs, job loss, or a child aging out of the order. The 2024 SB 343 changes to the formula can themselves be a basis for review.

In California, child support generally continues until the child turns 18. If the child is still a full-time high school student and not self-supporting at 18, support continues until graduation or age 19, whichever comes first. Support may continue indefinitely for a child who is incapacitated from earning a living and without sufficient means. California courts generally cannot order parents to pay for college as part of guideline child support.

Yes. Under Cal. Fam. Code § 4062, work-related childcare costs and the cost of the child's health insurance are mandatory additional support (add-ons) on top of the base § 4055 formula amount. These costs are generally divided between the parents in proportion to their net incomes. This calculator adds the higher earner's net-income share of these costs to the formula result.

This calculator provides an estimate based on the California child support guideline. Actual court-ordered support may differ because California uses a precise statewide algebraic formula and judges may deviate from the guideline based on factors including the child's needs, extraordinary expenses, the financial circumstances of each parent, and the standard of living. Consult a California family law attorney for an accurate assessment.