California Child Support: How the Formula Works (2026)

Picture a mom who brings home $3,000 a month after taxes. Her child's father nets $6,000 and has their daughter one day in five. Run through the state guideline, those numbers produce about $1,260 a month in California child support. That figure is not a judge's guess. It comes from a formula written into the Family Code.

The incomes are made up, but the math is real. This guide takes that formula apart, then covers the two ways to get an order, the costs added on top, and what the state can do when money stops coming. It explains how the system works and is not legal advice. Every rule below was read on the statute or agency page linked beside it on October 17, 2026.

$2,929 a month: the 2026 low-income line · 20% or $50: change that can trigger a review · $100 / $200: CalWORKs pass-through · 10%: yearly interest on unpaid support

In one minute

• The California child support guideline amount is presumed correct, and a judge needs a stated reason to order a different one
• Time with the children moves the amount along with income
• A paying parent who nets under $2,929 a month can get a low-income adjustment in 2026
• The local child support agency costs a receiving parent at most $35 a year
• A change in the amount reaches back only to the day someone asked for it

Two doors to an order: the court or the local child support agency

There are two ways into the California child support system. The first is the family court, where a parent files papers in an existing divorce or parentage case, or opens a new one. The second is the local child support agency (LCSA), a county office that works under the state Department of Child Support Services (DCSS) and can ask the court for an order for you (California Courts Self-Help Guide).

Either parent, or a legal guardian, can enroll with the agency, with or without an existing order, and there is no income test (DCSS enrollment page). The agency can find the other parent, establish legal parentage, get a support order and a medical support order, and then collect and track payments.

The agency has limits. It cannot handle custody or visitation, file a divorce, get a restraining order or set spousal support, and it does not act as either parent's lawyer (California Child Support Services). For a custody fight, the guide to custody mediation covers what happens in that separate process.

Question	Family court on your own	Local child support agency
Cost to the parent asking	Court filing fees unless a fee waiver is granted	Free to the payer; up to $35 a year to a receiving parent not on cash aid
Main forms	FL-260 to open a case, or FL-300 in an existing one, plus FL-150 or FL-155	Online enrollment; the agency serves a Summons and Complaint
Calculator used	Any of the five calculators the Judicial Council certifies	The DCSS guideline calculator only
Custody and visitation	Can be decided in the same case	Not handled

The court forms come from the Self-Help Guide's child support forms list. The agency steps, from enrollment to the Summons and Complaint and a possible "Stipulated Agreement" that avoids a hearing, are set out on the DCSS how-it-works page. If you get cash aid for the children, the agency can become part of the case.

The California child support formula, one letter at a time

The statewide guideline is a single line: CS = K[HN - (H%)(TN)] (Family Code 4055). Each letter stands for one number taken from the two households.

• CS is the monthly support for one child.
• HN is the higher earner's net monthly disposable income.
• TN is both parents' net incomes added together.
• H% is the share of time the higher earner has primary physical responsibility for the children.
• K is the share of combined income set aside for the children, from the bands in the table below.

K has two parts. The first is 1 plus H% when the higher earner has the children half the time or less, or 2 minus H% when it is more. That first part is multiplied by a fraction picked by combined net income.

Combined net income a month (TN)	Fraction used inside K
$0 to $2,900	0.165 + TN / 82,857
$2,901 to $5,000	0.131 + TN / 42,149
$5,001 to $10,000	0.25
$10,001 to $15,000	0.10 + 1,499 / TN
Over $15,000	0.12 + 1,200 / TN

These bands date from Senate Bill 343, which rewrote the guideline, operative September 1, 2024. If the answer comes out negative, the lower earner pays the higher earner instead. Both rules sit in the same section of the code.

What counts as net disposable income

For California child support, gross income is read broadly: wages, commissions, bonuses, rents, pensions, unemployment and disability benefits, Social Security and more (Family Code 4058). Child support you already receive does not count, and neither does need-based public aid such as CalWORKs or CalFresh.

When a parent's income is unknown, the court has to look at earning capacity. It can also use earning capacity in place of a known income, after weighing work history, skills, health, the local job market and the children's interests. Time in jail or prison is not treated as choosing not to work.

From gross income, the court subtracts the taxes a parent actually owes, Social Security and Medicare tax, mandatory union dues and retirement, health insurance premiums, state disability insurance and support paid for other children (Family Code 4059). What remains is the net figure that goes into the formula.

Running the numbers for one made-up family

Back to the opening example. The father nets $6,000, so he is the higher earner and HN is $6,000. The mother nets $3,000, so TN is $9,000. He has their daughter 20% of the time, so H% is 0.20.

Combined income of $9,000 falls in the $5,001 to $10,000 band, so the fraction is 0.25. K is (1 + 0.20) x 0.25, which is 0.30. Inside the brackets, $6,000 minus 0.20 x $9,000 leaves $4,200. Then 0.30 x $4,200 gives $1,260 a month for one child.

More children do not simply multiply the bill by the number of kids. The code multiplies the one-child figure by 1.6 for two children, 2 for three, 2.3 for four and 2.5 for five. For this family, that comes to $2,016, $2,520, $2,898 and $3,150 a month.

Unless the court orders otherwise, the youngest child is assigned the one-child amount and each older child the difference between steps. That matters later, because when the oldest child ages out, the order drops by that child's slice, not by an even share.

How timeshare moves the number

Time with the children is the second big input in California child support. Keep the same incomes and change only how often the father has the child, and the guideline falls quickly. At equal time, though, it does not reach zero, because his income is double hers.

The formula uses the approximate share of time each parent has primary physical responsibility for the children, so a calendar of overnights is worth keeping. If you are setting up a shared plan, the 50/50 custody schedule guide shows how common rotations add up across a year.

The low-income adjustment and the $2,929 line

California child support has a built-in cushion for low earners. When the paying parent's net income is below what a full-time minimum wage job earns before taxes, the law presumes he is entitled to a low-income adjustment. The other parent can argue it would be unjust. Since September 1, 2024, the line has been tied to the state minimum wage at 40 hours a week, 52 weeks a year.

California's minimum wage rose to $16.90 an hour on January 1, 2026 (Department of Industrial Relations). That puts the 2026 line at $2,929 a month, the figure the Judicial Council lists (Judicial Council, guideline support calculators).

The adjustment can shrink the formula amount by up to a fraction: the line minus the payer's net income, divided by the line. A payer netting $2,000 can have the amount cut by up to 31.7%, and a judge chooses where in that range to land.

A second protection applies on top. If the guideline amount, after the adjustment, still takes more than half of a low-income payer's net income, the court can lower it to that 50% mark (Family Code 4057).

Costs added on top of the guideline

Two add-ons to California child support are required by law. Child care that a parent actually pays so she can work or train for work must be added, and so must reasonable uninsured health costs for the children (Family Code 4062). A court may also add school or special-needs costs and travel for visits.

These extras are usually split by the parents' net incomes, not down the middle (Family Code 4061). In the example, she nets $3,000 and he nets $6,000. Before base support moves between them, he would carry two-thirds of the child care bill and she one-third.

The code then adjusts the split. His net income is reduced by the $1,260 he pays, while hers is not raised by the support she receives. That leaves him about 61% of the child care bill and her about 39%.

When a judge can order a different amount

The guideline amount is presumed correct, but the presumption can be rebutted. The court has to state its reasons, in writing or on the record. The listed reasons include an agreement between the parents, a very high income where the formula would exceed the children's needs, and a parent who is not spending on the children in line with their time.

Special circumstances also count. Examples in the code include different time-sharing for different children, equal time where one parent spends a much larger share of income on housing, and a child with special medical needs. A mom who suspects the other parent is hiding income can ask for help; free legal aid for single mothers lists where to start.

Changing an order: review and adjustment or form FL-300

With an agency case, either parent can ask for a "review and adjustment" at no charge. A modification is generally possible when the order would change by 20% or $50, whichever is less (DCSS modification page). A job loss, a raise, new custody time or a disability are typical reasons.

Without the agency, a parent files a Request for Order, form FL-300, or both parents sign a written agreement for the judge. Do not wait. A judge can change the amount only back to the day the request was filed, so months of a higher order before that stay owed.

A parent paying support who is jailed for 60 days in a row or longer can ask the agency to lower the order with a special form. Since January 1, 2024, an order put on hold during a jail stay resumes on the first day of the tenth month after release, or once the parent finds work, whichever comes first (DCSS on Assembly Bill 1148).

The end date: 18, 19 and the high school rule

California child support usually ends at 18. It continues for an unmarried 18-year-old who is a full-time high school student and not self-supporting, until the child finishes 12th grade or turns 19, whichever comes first (Family Code 3901).

Support can also end earlier if the child marries, joins the military or is emancipated, and it can continue for an adult child who is disabled and cannot self-support. Past-due support does not end with the order. The agency can keep collecting until the balance and its interest are paid (DCSS frequently asked questions).

How the money moves

Every California child support order includes an earnings assignment, which tells the payer's employer to send support straight from the paycheck (Family Code 5230). Payments run through the State Disbursement Unit, and a payer whose support is not taken from wages can pay online, by phone or at a county kiosk (DCSS, paying support).

A receiving parent can choose direct deposit, an Electronic Payment Card that works like a prepaid Mastercard, or a paper check, which DCSS calls slower and less secure (DCSS, receiving support).

If you receive CalWORKs: the $100 and $200 pass-through

A family on CalWORKs cash aid signs its support rights over to the state. The first $100 a month of current California child support goes to a family with one child, or up to $200 with two or more children, and that amount does not reduce the cash grant (DCSS, more money to families). The rest repays aid.

Once a family leaves CalWORKs, the picture changes. Under Assembly Bill 207, since May 1, 2024, current support and money collected on debt owed to the government both go to former CalWORKs families. Full pass-through for families still on aid would need new state funding, says a February 2026 report to the Legislature, which put the average monthly pass-through between $16.43 and $25.94 (DCSS report on full pass-through).

If cash aid is not enough to cover rent while support is set up, the California grants guide lists other help to apply for at the same time. For rent itself, see the California housing assistance guide.

Unpaid support: interest, license holds and passports

Unpaid California child support builds interest at 10% a year (Code of Civil Procedure 685.010). The 10% rate still applied when this guide was checked, and the agency lists it first among the costs of paying late.

The agency can intercept state and federal tax refunds, unemployment, disability and workers' compensation benefits, and lottery winnings. It can place liens on property and bank accounts and report the debt to credit bureaus.

Licenses have a floor. Since January 1, 2025, an agency cannot suspend a driver's license over support unless the payer's household income is above 70% of the area median income for their county (DCSS on Senate Bill 1055). The agency's FAQ says professional licenses can still be suspended.

Passports are another pressure point. Federal law denies a passport to a parent who owes $2,500 or more, and since September 28, 2026 the State Department has been revoking active passports for parents who owe $15,000 or more (DCSS passport page).

Before a hearing or an agency interview

• Two months of pay stubs, or a profit and loss statement if self-employed
• A calendar of overnights for the past year
• Child care receipts and health insurance statements
• A printout from the DCSS guideline calculator with your numbers
• Any order or agreement already signed

If the father is a danger to you or the children, support can wait while safety comes first; the emergency custody order guide explains that process. Families comparing states can read how child support works in Texas, where a percentage rule replaces the formula.

Common questions about California child support

Can I get California child support if we were never married?

Yes. Marriage is not required. If legal parentage is not yet established, the local child support agency can establish it free of charge and then ask the court for an order. A parent filing without the agency can use form FL-260 to open a case asking for custody and support, and FL-150 to show income.

Is the DCSS guideline calculator's answer the final amount?

No. The DCSS guideline calculator gives an estimate using the same guideline the courts use, but a judge or child support commissioner sets the final number. Results depend on each parent's income, tax filing status, timeshare, add-ons and any departure from the guideline that the court allows, so keep a copy of the inputs you used for each run.

Can child support be backdated to when we split up?

A change to an existing order can reach back only to the date someone filed the request, not to the date income or custody changed. That is why the Self-Help Guide tells parents not to wait. For a first order, ask the agency or a family law facilitator how far back support can start in your case.

What happens to support if the paying parent goes to jail?

Jail or prison time is not treated as voluntary unemployment, so the order can be lowered. A parent jailed 60 days in a row or longer can ask the agency for a review. If the order was paused during the stay, payments restart on the first day of the tenth month after release, or once the parent finds work.

Do I pay a fee to use the child support agency?

Services are free for the parent who pays California child support. A receiving parent who does not get cash aid can be charged a federal annual fee of no more than $35, and it applies only on cases that collected at least $550 that year. Families on CalWORKs do not pay it. The notice arrives each October.

Sources

• California Legislature. Family Code section 4055 (statewide uniform guideline, operative September 1, 2024). leginfo.legislature.ca.gov (retrieved October 17, 2026)
• California Legislature. Family Code section 4057 (rebuttable presumption). leginfo.legislature.ca.gov (retrieved October 17, 2026)
• California Legislature. Family Code section 4058 (annual gross income). leginfo.legislature.ca.gov (retrieved October 17, 2026)
• California Legislature. Family Code section 4059 (net disposable income). leginfo.legislature.ca.gov (retrieved October 17, 2026)
• California Legislature. Family Code section 4061 (sharing add-on costs). leginfo.legislature.ca.gov (retrieved October 17, 2026)
• California Legislature. Family Code section 4062 (additional child support). leginfo.legislature.ca.gov (retrieved October 17, 2026)
• California Legislature. Family Code section 3901 (support past age 18). leginfo.legislature.ca.gov (retrieved October 17, 2026)
• California Legislature. Family Code section 5230 (earnings assignment order). leginfo.legislature.ca.gov (retrieved October 17, 2026)
• California Legislature. Code of Civil Procedure section 685.010 (interest on judgments). leginfo.legislature.ca.gov (retrieved October 17, 2026)
• Judicial Council of California. Guideline Support Calculators (low-income adjustment threshold, updated August 10, 2026). courts.ca.gov (retrieved October 17, 2026)
• California Department of Industrial Relations. Minimum wage rises to $16.90 per hour on January 1, 2026 (news release 2025-118). dir.ca.gov (retrieved October 17, 2026)
• California Courts. Self-Help Guide, Child support (changes and agency cases). selfhelp.courts.ca.gov (retrieved October 17, 2026)
• California Courts. Self-Help Guide, Child support forms (FL-260, FL-300, FL-150). selfhelp.courts.ca.gov (retrieved October 17, 2026)
• California Child Support Services. Home page (what agencies can and cannot do). childsupport.ca.gov (retrieved October 17, 2026)
• California Child Support Services. Enroll for Support (who can enroll). childsupport.ca.gov (retrieved October 17, 2026)
• California Child Support Services. How It Works (10 steps). childsupport.ca.gov (retrieved October 17, 2026)
• California Child Support Services. Guideline Calculator (estimate only). childsupport.ca.gov (retrieved October 17, 2026)
• California Child Support Services. Change a Child Support Amount (review and adjustment). childsupport.ca.gov (retrieved October 17, 2026)
• California Child Support Services. Paying Support (payment options for payers). childsupport.ca.gov (retrieved October 17, 2026)
• California Child Support Services. Receiving Support (payment options). childsupport.ca.gov (retrieved October 17, 2026)
• California Child Support Services. Frequently Asked Questions (fees, interest, enforcement, end date). childsupport.ca.gov (retrieved October 17, 2026)
• California Child Support Services. Passport Denial or Revocation (thresholds). childsupport.ca.gov (retrieved October 17, 2026)
• California Department of Child Support Services. Release of suspended licenses as SB 1055 takes effect (January 2, 2025). dcss.ca.gov (retrieved October 17, 2026)
• California Department of Child Support Services. Suspension of payment for formerly incarcerated parents extended (AB 1148, November 13, 2024). dcss.ca.gov (retrieved October 17, 2026)
• California Department of Child Support Services. Child Support Services to give more money to families (AB 207, May 6, 2024). dcss.ca.gov (retrieved October 17, 2026)
• California Department of Child Support Services. Supplemental Report of the 2024-25 Budget Act: Full Pass-Through of Child Support (February 2026). dcss.ca.gov (retrieved October 17, 2026)