In California, child support is a court-ordered monthly payment from one parent to the other to cover a child’s living expenses, calculated using a statewide formula that both parents and judges are required to follow. The two biggest inputs are each parent’s income and how much time each parent has physical custody. Both parents share the legal duty to support their children regardless of whether they were ever married.1California Legislative Information. California Family Code 3900 – Duty of Parent
How the Amount Is Calculated
California uses a single algebraic formula, set out in Family Code section 4055, for every case in the state.2California Legislative Information. California Family Code 4055 – Statewide Uniform Guideline The formula runs on two numbers: each parent’s net monthly disposable income and the percentage of physical custody time held by the higher earner.
Net disposable income begins with gross income and subtracts federal and state income taxes, Social Security and Medicare, mandatory retirement contributions, health insurance premiums, union dues, and certain necessary job-related expenses. Hardship deductions for other children a parent is supporting may also reduce the figure.
The custody timeshare is decisive. The more overnight time the higher-earning parent has with the child, the lower the payment, because that parent is already covering daily expenses during their time. Small shifts in the schedule can move the monthly obligation by hundreds of dollars.
Mandatory Add-Ons
On top of the base guideline amount, the court must order both parents to share two categories of costs: childcare tied to a parent’s employment or job training, and the child’s uninsured healthcare expenses.3California Legislative Information. California Family Code 4062 – Additional Child Support These are usually split in proportion to each parent’s income, though the court can allocate them differently.
What Counts as Income
California defines gross income broadly. It includes wages, salaries, bonuses, commissions, rental income, dividends, pensions, unemployment and disability benefits, Social Security, severance pay, and workers’ compensation. Military housing and food allowances also count.4California Legislative Information. California Family Code 4058 – Annual Gross Income Spousal support received from someone outside the current case is included. Child support received for children from a different relationship is not.
Self-employment income is gross business receipts minus the expenses needed to run the business. Judges are not required to accept every deduction the IRS allows. Personal expenses dressed up as business ones, above-market salaries paid to relatives, and depreciation that reduces taxable income without reducing actual cash can all be added back to a self-employed parent’s income for support purposes.
When a Parent Is Unemployed or Underemployed
Quitting a job or taking a lower-paying one to shrink a support obligation doesn’t necessarily work. When a parent’s income is unknown, the court must consider that parent’s earning capacity. Even when income is known, the judge has discretion to substitute earning capacity if doing so serves the children’s best interests.4California Legislative Information. California Family Code 4058 – Annual Gross Income Earning capacity is measured against the parent’s work history, skills, education, age, health, criminal record, and the local job market.
One exception matters: a parent who is incarcerated or involuntarily institutionalized cannot be treated as voluntarily unemployed when a court sets or modifies support.4California Legislative Information. California Family Code 4058 – Annual Gross Income
When the Court Can Order a Different Amount
The guideline amount is presumed correct, and that presumption is strong. A parent can overcome it by proving the formula would be unjust in the specific case, and the judge must explain any deviation in writing or on the record.5California Legislative Information. California Family Code 4057 – Presumption of Correctness
The most common reasons for deviating:
- Very high income, where the formula amount would exceed what the children actually need.
- A stipulated agreement between the parents. If they agree to a below-guideline amount, the court will only approve it after confirming both understand their rights, are not being coerced, and the children’s needs will still be met.6California Legislative Information. California Family Code 4065 – Stipulated Agreement
- Special circumstances such as extraordinary medical needs, sharply unequal housing costs despite equal timeshare, or a case with more than two legal parents.5California Legislative Information. California Family Code 4057 – Presumption of Correctness
If parents stipulate to below-guideline support, the parent receiving support can later request a modification up to the full guideline amount without proving any change in circumstances.6California Legislative Information. California Family Code 4065 – Stipulated Agreement The below-guideline number is essentially a floor with an open ceiling.
Health Insurance Coverage
Every child support order must address health insurance for the child. If either parent has access to coverage at a reasonable cost, the court will order that parent to maintain it. Coverage is presumed reasonable if adding the child costs no more than five percent of that parent’s gross income, measured as the difference between self-only and family coverage rather than the total premium.7California Legislative Information. California Family Code 3751 – Health Insurance Coverage
If no affordable coverage exists at the time of the order, the order will require the parent to obtain it once it becomes available at a reasonable cost. Parents receiving the low-income adjustment are generally exempt from the health insurance mandate unless the court finds exempting them would be unjust.7California Legislative Information. California Family Code 3751 – Health Insurance Coverage
How to Get a Support Order
There are two paths.
Through Family Court
If you already have a family law case, such as a divorce, legal separation, or parentage action, you request support inside that case by filing a Request for Order. The other parent must be formally served, and both attend a hearing where the judge applies the guideline. The filing fee for a motion in a family law case is $60,8California Courts. Statewide Civil Fee Schedule and a fee waiver is available if you cannot afford it.
Through the Department of Child Support Services
Parents who are not already in a family court case, or who want help with the process, can open a case with their local child support agency, which operates under the Department of Child Support Services (DCSS). This route is free. The agency will locate the other parent if needed, establish legal parentage, file the court papers, and obtain the order.9California Legislative Information. California Family Code 17400 – Local Child Support Agency Court filings made by DCSS are also exempt from fees.8California Courts. Statewide Civil Fee Schedule The tradeoff is caseload; you have less control over timing and strategy than with a private attorney.
How Payments Are Made
Almost all California child support payments run through the State Disbursement Unit (SDU), not directly between parents. Most orders include a wage assignment: the paying parent’s employer deducts support from each paycheck and sends it to the SDU.10California Child Support Services. CA Child Support Services Once an employer receives the withholding order, they have 10 days to begin deducting.11California Courts. Paying Child Support
Self-employed parents, or anyone without a traditional paycheck, can pay through the Child Support Payment Center, which accepts Apple Pay, Google Pay, PayPal, and Venmo.10California Child Support Services. CA Child Support Services Paying through the SDU creates an official record. Cash handed directly to the other parent, even with a receipt, is risky; without the SDU record, proving those payments happened can be difficult if a dispute arises.
Taxes
Child support is tax-neutral. The paying parent cannot deduct it, and the receiving parent does not report it as income.12IRS. Alimony, Child Support, Court Awards, Damages It doesn’t appear on either return. This is different from spousal support, which has its own rules.
Changing an Existing Order
An order stays in effect until a court changes it. Parents cannot agree between themselves to modify the amount; even a handshake deal to accept less will not stop arrears from accruing at the original court-ordered figure. To modify, the parent seeking the change files a Request for Order showing a significant change in circumstances since the last order.
Common grounds:
- A significant increase or decrease in either parent’s earnings.
- A shift in how much time the child spends with each parent.
- New needs, such as a medical condition, that require greater financial support.
- An existing below-guideline stipulation, which either parent can move to bring up to guideline without proving changed circumstances.6California Legislative Information. California Family Code 4065 – Stipulated Agreement
A modification takes effect from the date the request is filed, not the date your circumstances actually changed. If you lose your job in January and don’t file until March, the two intervening months accrue at the old rate and become arrears that cannot be forgiven. File as soon as the change happens.
What Happens If Payments Aren’t Made
Unpaid support, called arrears, begins accruing interest at 10 percent per year the moment it is missed.11California Courts. Paying Child Support The rate is set by California’s general judgment interest statute and applies automatically.13Justia Law. California Code of Civil Procedure 685.010-685.110
DCSS can act without returning to court for each step. Its main tools:
- Wage withholding through an income withholding order sent to the employer.11California Courts. Paying Child Support
- Interception of state and federal tax refunds, lottery winnings, and certain disability payments.
- Suspension of driver’s, professional, or recreational licenses for seriously delinquent accounts.
- Liens on real estate that block a sale or refinancing until the debt is paid.
Passport Denial
When arrears exceed $2,500, the state can certify the debt to the federal government, and the U.S. Department of State will deny any new passport, renewal, or replacement until the debt is resolved.14Office of the Law Revision Counsel. 42 U.S. Code 652 – Duties of Secretary Parents often discover this at the passport office, when it’s too late to travel on schedule.
Bankruptcy Doesn’t Erase It
Filing bankruptcy will not discharge child support. Federal law exempts domestic support obligations from discharge in both Chapter 7 and Chapter 13 cases.15Office of the Law Revision Counsel. 11 U.S. Code 523 – Exceptions to Discharge The arrears and interest survive the bankruptcy and stay fully enforceable.
If One Parent Moves Out of State
The California order remains in effect. Under the Uniform Interstate Family Support Act, adopted by all 50 states, a single controlling order governs the obligation no matter where the parents live. The California order can be registered and enforced in the new state, or DCSS can coordinate enforcement across state lines.
When Child Support Ends
Child support in California generally terminates when the child turns 18.1California Legislative Information. California Family Code 3900 – Duty of Parent The main exception: if the child is 18, still in high school, attending full-time, unmarried, and not self-supporting, the obligation continues until the child finishes 12th grade or turns 19, whichever comes first. A child with a documented medical condition that prevents full-time attendance may still qualify without full-time enrollment.
Support also ends earlier if the child marries, enters a registered domestic partnership, is emancipated by court order, or dies. Turning 18 and enrolling in college does not extend support; California does not require parents to pay court-ordered child support for adult college students. Parents can voluntarily agree to keep paying for college or other purposes, but that agreement sits outside the court order.