California child support has no fixed average — the amount depends on each parent's income, custody time, and the number of children

There is no single "average" child support payment in California because the law calculates support based on the specific details of each family. Two parents earning the same income might pay very different amounts if one has the children more days per year, or if one parent pays for health insurance. The state uses a formula that starts with both parents' gross income, adjusts for how much time each parent spends with the children, and accounts for existing support obligations.

What matters more than an average is understanding how your own situation would be calculated. The formula itself is public, and you can work through it with your actual numbers. This section explains what goes into that calculation so you know what information you will need and what the court will consider.

Key Takeaways

  • California calculates child support using a formula based on both parents' gross income, the percentage of time each parent has the children, and the number of children.
  • The guideline amount is what the court uses unless both parents agree to something different or the judge finds the guideline would be unjust.
  • Income includes wages, self-employment earnings, rental income, and some benefits — not just a paycheck.
  • The percentage of time each parent spends with children (called "custody percentage") directly affects the amount, so custody arrangements matter as much as income.
  • You can calculate an estimate using the state's online calculator or by working through the formula with a family law attorney.

How the California formula works

California uses what is called the guideline formula, set out in Family Code Section 4055. The formula takes both parents' gross income, multiplies it by a percentage that depends on how many children there are, then adjusts based on how much time each parent spends with the children. The result is the guideline amount — the amount the court will order unless there is a reason not to.

The formula looks like this in its simplest form: (Parent A's income + Parent B's income) × percentage for number of children × adjustment for custody time = guideline support. But "income" and "custody time" each have their own rules, which is why two families with similar paychecks can end up with very different orders.

The guideline is not a ceiling or a floor. A judge can order more or less than the guideline amount if the judge finds that explore the guideline would be unjust or inappropriate given the circumstances. Common reasons include a parent's extraordinary expenses, a very high income, or a child with special needs. But the guideline is where the calculation starts.

What counts as income for child support

Income for child support purposes is broader than just a salary. It includes wages and salary, self-employment income, rental income, interest and dividends, social security benefits (with some exceptions), disability benefits, workers' compensation, unemployment insurance, and income from a pension or retirement account. It also includes bonuses and commissions if they are regular.

Income does not include certain means-tested benefits like CalFresh (food stamps) or CalWORKs (cash information), or child support the parent is already paying for other children. If a parent is voluntarily unemployed or underemployed — meaning they could earn more but choose not to — the court may "impute" income, or assume they are earning more than they actually are. This prevents a parent from lowering their support obligation by quitting their job.

Both parents must disclose their income on a form called the Income and Expense Declaration (Form FL-150). This form asks for the last two years of tax returns, recent pay stubs, and details about any other income. If a parent does not disclose income truthfully, the other parent can request a hearing to correct it.

How custody time affects the amount

The percentage of time each parent spends with the children directly changes the support calculation. If one parent has the children 70 percent of the time and the other has them 30 percent, the formula adjusts differently than if the split is 50-50. More time with the children generally means lower support from that parent, because they are already spending money on the children's daily care.

Custody time is measured as the number of overnights per year. A parent who has the children every other weekend plus one weeknight, for example, has a different percentage than a parent who has them every weekend. The court looks at the actual schedule, not what the parents say they want — so if you have been following a certain schedule for months, that is what counts, even if the custody order says something different.

If the parents have exactly equal time (50-50 custody), the formula still applies, but the adjustment is different. Neither parent is considered the "primary" parent, so the calculation reflects that both are sharing the day-to-day costs.

What the guideline amount typically covers

The guideline child support amount is meant to cover the child's ordinary living expenses: food, clothing, shelter, utilities, and transportation. It does not automatically include health insurance premiums, childcare costs, or uninsured medical expenses — those are usually ordered separately. However, the formula does account for the cost of health insurance by allowing a deduction from income if a parent is paying for it.

Childcare costs that allow a parent to work are deductible from income before the formula is applied, which lowers the guideline amount. This recognizes that if a parent is paying $1,200 a month for childcare so they can earn $4,000 a month, their actual available income is lower. Similarly, if a parent is paying child support for other children, that amount is deducted from their income before the guideline is calculated.

Extraordinary expenses — such as private school tuition, special needs therapy, or sports — are usually split between the parents in addition to the guideline amount, though the court has discretion about how to divide them.

Using the state calculator and getting an estimate

California provides a free online calculator on the Judicial Council website that walks you through the formula step by step. You enter both parents' gross income, the number of children, the percentage of time each parent has custody, and any childcare or health insurance costs. The calculator then shows you what the guideline amount would be. This is a useful starting point if you want to understand what your situation might look like.

The calculator is not a legal information — it is an estimate based on the numbers you enter. If you and the other parent disagree about income, custody time, or what should be deducted, the calculator will show different results depending on which numbers you use. For that reason, many people work with a family law attorney to verify the numbers before going to court.

If you are representing yourself, you can also request that the court's family law facilitator help you fill out the Income and Expense Declaration correctly. The facilitator cannot give legal information, but they can explain what information goes where and help you understand the forms.

When the guideline amount changes

The guideline amount can change if either parent's income changes significantly, if custody time changes, or if the number of children changes (for example, if a child turns 18 and is no longer in school). Either parent can request a modification by filing a Request to Modify Child Support Order with the court. The court will not modify the order unless there has been a substantial change in circumstances — usually a change of 10 percent or more in income or a significant change in custody time.

If a parent's income drops because they lost their job, they should request a modification as soon as possible. If they wait months to ask, the court may still lower the amount going forward, but it usually will not go back and erase the payments that were due during the waiting period. The same is true if income increases — the other parent can request a modification, and the increase applies from the date the request is filed, not retroactively.

Modifications are handled through the same court that issued the original order, or through the local child support agency if the case is being enforced through the Department of Child Support Services.

Frequently Asked Questions

Does California have a minimum or maximum child support amount?

California has no legal minimum, but courts rarely order less than $50 per month per child. There is no maximum either — the guideline formula applies to all income levels, though judges have discretion to order more or less than the guideline for high-income parents. If a parent earns over $250,000 per year, the court must state its reasons for any order that differs from the guideline.

What if both parents have the same income and 50-50 custody?

If both parents earn the same amount and have equal custody time, the guideline amount is usually zero or very close to it, because neither parent is considered to be supporting the other. However, a parent can still request that the other parent contribute to specific expenses like health insurance, childcare, or extraordinary costs.

Can parents agree to pay less than the guideline amount?

Yes, parents can agree to any amount they choose, but the court must approve it. The judge will review the agreement to make sure it is not unfair to the child. If one parent is receiving public benefits like CalWORKs, the state may object to an agreement that is below the guideline, because the state wants to recover some of its costs.

How long does child support last in California?

Child support continues until the child turns 18 and is no longer in high school, or until age 19 if the child is still in high school. It can also continue past age 18 if the child is disabled and unable to support themselves, but that requires a separate court order.

What happens if a parent does not pay the ordered amount?

The other parent or the Department of Child Support Services can enforce the order through wage garnishment, bank levies, license suspension, or contempt of court proceedings. If a parent falls behind, interest accrues on the unpaid amount. The parent owing support can request a modification if their circumstances have changed, but they cannot straightforward stop paying.