Child support in California.
What the state’s own guideline says, where the number comes from, and the one figure that moves it more than anything you will argue about.
See a different stateCalifornia
California does not look up a number on a table. It runs a formula: CS = K [HN − (H%)(TN)]. TN is both parents' combined monthly net disposable income, HN is the higher earner's net disposable income, H% is the share of time the higher earner has primary physical responsibility for the child, and K is a factor set by statute that rises and falls with income. Because parenting time is inside the formula, every extra night you have with your child changes the number — there is no cliff you have to cross.
How California works out the number
Authority: Cal. Fam. Code §§ 4050–4076 (statewide uniform guideline); the formula is at Fam. Code § 4055, amended by SB 343 (Stats. 2023) with the new formula and low-income adjustment operative September 1, 2024There is no overnight threshold. Parenting time enters the formula directly as H% — the percentage of time the higher-earning parent has primary physical responsibility for the child. The amount moves continuously as that percentage moves.
Use the state’s own calculator, not ours
California publishes this itself, free. We are not going to build a competing calculator and ask you to trust it — this is the one a judge will recognize.
Open the California calculator →What goes into the calculation
What counts as income
The state's own calculator guide lists income as "Wages from a job," "Commissions," "Bonuses," "Self-employment earnings" and "Any payments or credits due or becoming due, regardless of the source, including lottery and prize winnings." Self-employment income is "gross income minus business expenses." That catch-all phrase is what sweeps in overtime and a second job. From gross income the court subtracts taxes, "mandatory union dues," "mandatory retirement contributions," "health premiums," child or spousal support actually being paid, and the costs of raising children from another relationship, to reach net disposable income.
When a judge can treat you as earning more
We could not read the imputation statute (Fam. Code § 4058) on the state's own legislative site — see blocked. California courts do have authority to base support on earning capacity rather than actual earnings. Treat the exact standard as unconfirmed and ask your local court's family law facilitator.
If you do not earn much
Family Code § 4055(b)(7). Since September 1, 2024 the state calculator guide describes the trigger as: the paying parent's "net disposable income per month … is less than the full-time minimum wage at 40 hour per week, 52 weeks per year." Before that change the trigger was a $1,500 net-disposable-income figure indexed for inflation, which the Judicial Council reported had risen to $2,056. If you are looking at an older order or an older calculator, it may still be using the old number.
Childcare and health insurance
California adds certain costs on top of the formula number ("add-ons") rather than building them into it. Health insurance premiums are also deducted from gross income when the court computes net disposable income. We could not read Family Code § 4062 on the state's legislative site, so the precise list of mandatory versus discretionary add-ons is unconfirmed here.
When a judge can depart from the number
The guideline figure is a rebuttable presumption and a judge must make findings to depart from it (Fam. Code §§ 4056–4057). We could not read those sections on the state's legislative site, so the exact required findings are unconfirmed here.
Two things surprise people here. First, California is one of the only states where parenting time is baked straight into the math — there is no magic number of overnights to hit, so a schedule change of a few nights a month moves the number. Second, the low-income rule changed on September 1, 2024, and so did the formula itself; if someone hands you a calculation from before that date, it is running on old law. Use the state's own calculator at childsupport.ca.gov, not a private one — in cases involving the local child support agency, the state calculator is the only one allowed.
Later on
When it ends
The courts' self-help site states support ends when the child "turns 18 and graduates from high school (if still in high school full time) or turns 19, whichever happens first." It also ends if the child marries or registers a domestic partnership, joins the military, is emancipated, or dies.
College and support after 18
The self-help site says support can continue past 18/19 if the child has a disability, or if the parents agree to it. California does not describe a general power to order college support over a parent's objection.
Changing the amount later
You ask the court to change the order when circumstances change. We could not confirm a specific percentage or dollar trigger on an official California source.
How far back a change can reach
The courts' self-help site is blunt about this: "A judge can only change the support amount as far back as the day you filed papers asking for a change." File the paperwork the day your income drops — waiting costs you money you cannot get back.
What we could not confirm
- California's official statute website blocks automated access, so we could not read the exact text of the formula's K-factor table, the income definition, the add-on list, or the deviation standard directly from the state's own site. Everything above comes from other official California sources — the Department of Child Support Services and the Judicial Branch. Before you rely on a specific number, run your figures through the state calculator or ask your court's family law facilitator.
- 3 official pages we tried to read refused automated access. We did not try to get around the block, so some detail above comes from a different official source rather than the one we would have preferred.
Compare all fifty states
The overnight thresholds, the ending ages and the college rules, side by side.
The rest of what we have written about California. Every figure is quoted from California’s own statute or its courts’ own published schedule, and carries the date we last checked it.