California sets child support with a statewide guideline formula, not a judge’s opinion. The formula takes both parents’ net disposable incomes and the percentage of time each spends with the children, and produces a figure courts are required to order unless there is a specific legal reason to depart from it.
That makes the outcome unusually predictable. It also means the two things worth understanding are what counts as income and how parenting time is measured, because those two inputs drive almost the entire result.
California uses the formula in Family Code section 4055, applied through certified software such as DissoMaster or the state’s free Guideline Calculator. In simplified form it asks:
The guideline figure is presumptively correct. A judge can only order something different for stated reasons, such as a child with extraordinary medical needs, a parent with exceptionally high income where the guideline exceeds the children’s needs, or parents who agree to a different figure and satisfy the court the children are adequately provided for.
California defines income broadly. It includes salary and wages, bonuses and commissions, self-employment earnings, rental income, investment returns, pensions, unemployment and disability benefits, and in some cases employer perks such as a car or housing allowance.
Two situations come up constantly:
Both parents disclose income on the FL-150 Income and Expense Declaration, which is part of your financial disclosures. Accuracy there feeds straight into the support number.
Timeshare is the input people most often underestimate. Support falls as the paying parent’s share of time rises, and the relationship is steep: moving from roughly 20% to 30% of overnights can change the monthly figure substantially even with identical incomes.
Timeshare is calculated on actual time with each parent, usually counted in overnights across the year. It comes directly from your parenting plan, which is why custody and support cannot sensibly be negotiated separately. Agreeing a schedule without knowing its support consequence is how people end up with a judgment that does not work financially.
A caution worth stating plainly: asking for more parenting time purely to reduce support, without intending to exercise it, tends to go badly. Courts can recalculate on actual practice, and arrears accrue from the date of the request to change.
The guideline figure is base support. California adds certain costs on top, usually split equally.
Mandatory add-ons, which the court must order:
Discretionary add-ons, which the court may order:
Health insurance premiums for the children must also be addressed, and the court will usually order whichever parent has reasonable access to coverage to maintain it.
In California, support continues until the child turns 18 and has graduated high school, or turns 19, whichever comes first. It ends earlier if the child marries, joins the military or becomes self-supporting. Support for a disabled adult child can continue indefinitely.
Child support is always modifiable. Unlike spousal support, parents cannot permanently bargain it away, because the right belongs to the child. Either parent can request a change when circumstances shift materially: income changes, a different parenting schedule, a change in childcare costs, or another child.
The critical timing rule: changes are only backdated to the date you file the request, never earlier. A parent whose income drops in January but who files in June owes the old amount for those five months, and unpaid California support accrues interest at 10% per year and never expires.
There is no flat figure. California applies a statewide guideline formula using both parents net disposable incomes, the percentage of parenting time, and the number of children. Courts use certified software such as DissoMaster, and the resulting figure is presumed correct unless a specific legal reason justifies departing from it.
Yes, and the effect is significant. Support falls as the paying parent share of time increases, counted in overnights across the year. Moving from around 20% to 30% of overnights can change the monthly figure substantially even when incomes stay the same.
Nearly all of it: wages, bonuses, commissions, self-employment income, rental income, investment returns, pensions, unemployment and disability benefits, and some employer perks. If a parent is voluntarily underemployed the court can impute income based on earning capacity instead of actual earnings.
Yes, but with limits. Parents can agree a figure above guideline freely. To agree below guideline they must tell the court they know the guideline amount, confirm the agreement is not coerced, and satisfy the judge the children needs are adequately met. Support can never be permanently waived.
When the child turns 18 and has graduated high school, or turns 19, whichever comes first. It ends sooner if the child marries, enters the military or becomes self-supporting. Support for a disabled adult child who cannot support themselves can continue indefinitely.
Childcare costs that allow a parent to work or train for work, and uninsured or unreimbursed medical costs for the children. Courts must order these on top of base support, usually split equally. Travel for visitation and educational or special needs costs are discretionary add-ons.
File a request with the court showing a material change of circumstances, such as a change in income, parenting time or childcare costs. Changes are only backdated to the date you file, never earlier, so file promptly. Unpaid support accrues 10% annual interest and does not expire.
California has strong enforcement: wage garnishment, bank levies, property liens, interception of tax refunds, suspension of driving and professional licences, passport denial and contempt proceedings. Arrears accrue interest at 10% per year and cannot be discharged in bankruptcy.
Child-related orders are the part of a California judgment judges review most closely, and guideline figures that do not add up are a common reason packets come back. Our guided program builds your parenting plan and support figures together, so the schedule and the numbers match, and a California divorce expert checks them before filing.
\$49.99 per month. No contract, cancel anytime.
