California child support is calculated by a formula, not a fixed amount

California does not set a flat dollar amount for child support. Instead, the court uses a formula that multiplies each parent's income by a percentage, then adjusts for custody time and other factors. The result varies enormously — from under $200 a month for a low-income parent with partial custody to several thousand dollars monthly for a high-earning parent with minimal custody time.

The formula itself is written into California Family Code Section 4055. It accounts for both parents' gross income, the number of children, and how much time each parent spends with the children. A judge can depart from the formula only if both parents agree or if the judge finds the formula would be unjust or inappropriate in that specific case.

Because the amount depends entirely on your income and custody arrangement, the only way to know what you will owe or receive is to run the numbers with your actual figures or have an attorney or mediator do it for you.

Key Takeaways

  • California calculates child support using a formula based on both parents' gross income, number of children, and custody time split — not a fixed statewide amount.
  • The formula typically results in the higher-earning parent paying the lower-earning parent, and the amount changes if either parent's income changes or custody time shifts.
  • Child support covers the child's ordinary living expenses: food, housing, utilities, clothing, school costs, and medical care — not extraordinary expenses like private school or sports unless the order specifies it.
  • The court can order support to continue past age 18 if the child is still in high school, and support stops automatically when the child turns 19 or graduates high school, whichever comes later.
  • If you cannot pay the amount ordered, you must file a request to modify the order; ignoring the obligation results in wage garnishment, license suspension, and debt collection.

How the California formula works

The formula multiplies each parent's gross monthly income by a percentage that depends on the number of children. For one child, the percentage is roughly 20 percent of the paying parent's income. For two children, it is roughly 32 percent. For three children, roughly 40 percent. For four or more children, the percentage increases further but is capped at a maximum of 50 percent of the paying parent's income.

The formula then adjusts for how much time each parent has the children. If one parent has the children 70 percent of the time and the other 30 percent, the calculation shifts to reflect that the parent with less time contributes more to support. The court also factors in tax benefits, health insurance costs, and childcare expenses that one parent pays.

The result is a monthly amount. If the paying parent's income changes — through a job loss, a raise, or a new job — either parent can ask the court to recalculate. The same applies if custody time changes significantly.

What child support actually covers

Child support in California is meant to cover the child's ordinary living expenses: food, housing, utilities, clothing, school supplies, and basic medical care. It is not meant to maintain the child's pre-divorce standard of living, though courts do consider both parents' income levels when setting the amount.

Extraordinary expenses — private school tuition, orthodontics, sports leagues, music lessons, summer camp — are usually not included in the base child support amount. Instead, the court often orders parents to split these costs separately, usually 50-50 or in proportion to their incomes. The order will specify which expenses are shared and how.

Health insurance for the child is typically ordered separately from child support. One parent is usually ordered to carry the child on their health plan, and the other parent reimburses half the premium cost. If neither parent has access to employer health insurance, the court may order the higher-earning parent to purchase a plan.

When child support starts and stops

Child support begins on the date the court order is signed, not retroactively to the date of separation — unless the court orders back support, which it can do if one parent was already providing support informally before the order was entered.

Support continues until the child turns 19 or graduates high school, whichever comes later. If the child is still enrolled in high school at age 19, support continues until graduation or age 19, whichever is later. Support stops automatically on that date; neither parent has to file paperwork to end it.

If the child is disabled and cannot support themselves, either parent can ask the court to extend support beyond age 19. This requires a separate request and proof of the disability.

Income used in the calculation

The formula uses gross income, not take-home pay. Gross income includes wages, salary, bonuses, commissions, self-employment income, rental income, interest and dividend income, and income from pensions or annuities. It also includes unemployment benefits and disability benefits.

Some income is excluded: means-tested public benefits like CalFresh or CalWORKs, Supplemental Security Income (SSI), and child support or spousal support received from another relationship. If a parent is voluntarily unemployed or underemployed — meaning they could earn more but choose not to — the court can impute income, meaning it assigns an income figure based on what they could earn.

Self-employed parents must provide tax returns and business records. If income fluctuates, the court may average it over several years or use the most recent year's return. A parent who claims very low income must be prepared to explain why and provide documentation.

Modifying the amount if circumstances change

If your income changes by more than 10 percent, or if custody time changes significantly, you can ask the court to recalculate child support. This requires filing a Request to Modify Child Support Order with the court that issued the original order. You must serve the other parent with a copy and give them time to respond.

The court will not modify the order unless there has been a material change in circumstances. A temporary job loss or a brief period of reduced hours usually does not may have access to. A permanent job change, a significant raise or demotion, or a shift in custody time does.

If you stop paying because you lost your job, the unpaid support becomes arrears — a debt that accumulates. The other parent can ask the court to enforce the order, and the court can garnish your wages, suspend your driver's license, intercept your tax refunds, or refer the debt to a collection agency. Filing a modification request before you fall behind protects you.

Enforcement and what happens if you do not pay

If a parent does not pay child support, the other parent can file a request for enforcement with the court. The court can order wage garnishment, which means the paying parent's employer withholds the support amount from each paycheck. The court can also suspend the paying parent's driver's license, professional license, or recreational license.

Unpaid child support can result in a lien on property, interception of state and federal tax refunds, and referral to a private debt collector. If the arrears are large enough, the paying parent can be held in contempt of court, which can result in jail time.

If you are unable to pay the full amount ordered, contact the court or a family law attorney immediately to request a modification. Ignoring the obligation does not make it go away; it only adds penalties and enforcement costs.

Frequently Asked Questions

Does child support change if I get a new job or lose my job?

Yes, but only if you file a request to modify the order. A job loss does not automatically lower your support obligation. You must file paperwork with the court showing the income change and ask for recalculation. If you wait and fall behind, you will owe arrears even if your income later increases again.

What if the other parent is self-employed or claims very low income?

The court can impute income — assign an income figure — if it believes a parent is deliberately underemployed or hiding income. You can request the court order the other parent to produce tax returns, business records, and bank statements. If the court finds the claimed income is unrealistic, it can set support based on what the parent could reasonably earn.

Can child support be waived or forgiven?

Not unilaterally. Both parents can agree in writing to modify or waive support, but the court must approve the agreement. A verbal agreement between parents is not enforceable. If you and the other parent agree to a different amount, you must file the agreement with the court for approval.

Does child support end if the child moves in with the other parent?

Not automatically. If custody changes, the paying parent must file a request to modify the order. The court will recalculate based on the new custody arrangement. If you do not file and the child moves in with you, you are still legally obligated to pay until the order is officially changed by the court.

What if I cannot afford the amount the court ordered?

File a request to modify the order immediately. Bring documentation of your current income, expenses, and any change in circumstances. The court can lower the amount if your income has decreased or your circumstances have changed. Do not simply stop paying; that creates arrears and triggers enforcement action.