California Child Support Calculator and
Guidelines Worksheet

The California child support formula is codified in California Family Code Section 4055. Use this calculator to estimate the amount of child support you may pay or receive under the California child support guideline calculator formula.

The state of California uses a complex algebraic child support formula — sometimes called the "Dissomaster" formula after the software courts use — that determines the amount of a child support order based on both parents' net disposable income, the percentage of time the child spends with each parent, and several statutory adjustments. This calculator provides only an estimate — guideline child support that may be ordered by a court depends on factors in the California child support case.

For legal advice about your child support estimate, consult experienced child support attorneys in your county.

California courts are required to follow these guidelines in calculating support for virtually every case. Deviation from the guideline child support amount requires written findings that the amount would be unjust or inappropriate.

The California Department of Child Support Services (DCSS) administers statewide enforcement, and every California county child support agency can help establish or modify monthly child support orders at no cost. Use this calculator to estimate your CA child support obligation before contacting an attorney.

Health insurance and work-related child care are mandatory add-ons to the monthly child support amount: the parent who provides health insurance receives a credit, and necessary child care costs are added to the base child support amount and divided between the parents in proportion to income. These add-ons often equal or exceed the base amount, making accurate estimation of the child support amount require a full set of financial inputs rather than a simple income lookup.

Under California's Income Shares model, the calculation begins by determining each parent's gross income from all sources, including wages, salaries, commissions, bonuses, self-employment income, rental income, and certain benefits. The court then applies allowable deductions — such as taxes, mandatory retirement contributions, and pre-existing child support obligations — to arrive at each parent's adjusted or net income.

Both incomes are combined to find the total household income available for child support.

The combined income figure is then matched against California's child support schedule (referenced in Income Shares model with algebraic formula using both parents' net disposable income and time-share percentage), which provides a base obligation amount for the number of children involved. For example, under a typical Income Shares schedule, parents with a combined monthly income of $8,000 and two children have a presumptive obligation of $1,400 per month.

Each parent's share is then calculated in proportion to their contribution to the combined income — if one parent earns 60% of the total, they are responsible for 60% of the base obligation.

Additional expenses are layered on top of the base obligation. Health insurance premiums for the child, work-related childcare costs, and extraordinary expenses (such as special education or medical needs) are typically added to the base figure and divided proportionally between the parents.

The custodial parent's share is assumed to be spent directly on the child, while the non-custodial parent's share becomes the child support payment.

The number of children is the most direct factor in any California child support calculation under the child support guidelines in Income Shares model with algebraic formula using both parents' net disposable income and time-share percentage. The basic child support obligation increases with each additional child, though not in a strictly linear fashion.

The amount of child support also depends on each parent's monthly gross income, which includes wages, salary, commissions, bonuses, and other recurring sources. The noncustodial parent's share is calculated based on their proportion of the combined monthly gross income.

Health care and child care costs play a major role. The parent who carries the child's health insurance receives a credit or offset, and unreimbursed medical expenses exceeding a threshold are typically split between the parents.

Child care costs necessary for employment or education are added to the basic child support obligation and divided proportionally between parents.

Children with special needs — whether physical, developmental, or educational — can significantly increase the amount of child support. California courts operating under Cal.

Fam. Code § 4055 have discretion to deviate upward from the guideline amount when a child requires therapies, specialized schooling, or ongoing medical treatment that exceeds ordinary expenses.

Similarly, extracurricular activities and private school tuition may be considered, though courts vary in how they treat these costs.

High-income cases present unique challenges. Where California's schedule under Income Shares model with algebraic formula using both parents' net disposable income and time-share percentage sets a maximum combined income threshold, courts exercise independent discretion above that cap rather than applying the standard table.

When a parent is voluntarily unemployed or underemployed, California courts may impute income — assigning an earning capacity based on the parent's education, work history, job market conditions, and prior earnings — to prevent artificially lowering the child support amount by choosing not to work or accepting a lower-paying job without justification.

California's child support obligation generally continues until the child reaches the age of majority under state law — check Cal. Fam.

Code § 4055 for the specific cutoff age, which may extend beyond 18 in certain circumstances such as a child still in high school or college. Support may also end earlier if the child becomes emancipated through marriage, military service, or court order.

Either parent may petition the court under Cal. Fam. Code § 4055 to modify a child support order when there has been a material change in circumstances. Common triggers include:

• A significant income change for either parent (a material change in circumstances — such as a significant income shift, change in custody arrangement, or change in the child's needs — is generally required to modify the existing order; the exact threshold under Cal. Fam. Code § 4055 controls for California)
• Loss of employment or onset of a disability
• A significant change in the child's medical, educational, or developmental needs
• A substantial change in the custody or parenting-time arrangement

The parent seeking modification bears the burden of proving that circumstances have genuinely changed since the last order.

Modifications in California under Cal. Fam.

Code § 4055 are not automatic — even when circumstances change, the existing order remains in effect until a court enters a new one. Filing promptly matters because modifications typically take effect from the date of the petition, not retroactively to when the change occurred.

Parents who delay filing risk accumulating arrears under the original order that cannot be forgiven, since federal law prohibits retroactive reduction of child support arrears. Families navigating this process should contact a California family law attorney to confirm the specific modification threshold and filing procedures that apply to their order.

California has multiple enforcement mechanisms under Cal. Fam.

Code § 4055 to ensure child support is paid. The most common tool is income withholding (wage garnishment), which is now mandatory for most new and modified child support orders.

Under an income withholding order, the obligor's employer deducts the support amount directly from their paycheck and sends it to the state disbursement unit. This approach removes the obligation from the paying parent's discretion and provides the custodial parent with reliable, timely payments.

When wage garnishment is insufficient or the obligor is self-employed, California can pursue additional enforcement actions:

• Intercepting federal and state tax refunds
• Placing liens on real and personal property
• Suspending driver's licenses and professional or occupational licenses
• Denying or revoking passport applications for arrears exceeding $2,500
• Reporting delinquent obligors to credit bureaus

Each tool creates significant practical consequences that apply without a separate court hearing.

In severe cases, California courts may hold a non-paying parent in contempt of court, which can result in fines, community service, or incarceration. Repeated willful failure to pay can lead to criminal prosecution under both state and federal law.

The Deadbeat Parents Punishment Act makes it a federal crime to willfully fail to pay child support for a child living in another state when the arrearage exceeds $5,000 or has been unpaid for more than one year. The federal Office of Child Support Services (OCSE) can assist custodial parents with enforcement at no cost.

To contact the California child support program directly, use the OCSE state programs directory.

The amount of parenting time each parent exercises directly affects the child support calculation in California. When the non-custodial parent has the child for a significant number of overnights — typically 25% or more of the year (approximately 92 overnights in many jurisdictions) — California's guidelines under Income Shares model with algebraic formula using both parents' net disposable income and time-share percentage apply a shared-custody or parenting-time adjustment that reduces the non-custodial parent's obligation.

A parent who has the child more often incurs more direct expenses for housing, food, and daily needs, so the transfer payment to the other parent reflects that shared financial responsibility.

In cases where parents share custody equally (50/50), California courts typically still calculate support based on the income differential between the parents. The higher-earning parent generally pays support to the lower-earning parent, even in a true 50/50 arrangement, because the child's standard of living should be roughly comparable in both households.

The amount is usually significantly lower than in a traditional custody arrangement as calculated under Income Shares model with algebraic formula using both parents' net disposable income and time-share percentage. Even small changes in the overnight count — such as moving from 120 to 128 overnights — can cross a threshold that triggers a meaningful change in the support calculation.

Use the California Custody Time Calculator to track overnights precisely and determine which parenting time threshold applies to your schedule.

The California child support calculator estimates support under the California child support formula in Family Code § 4055. California child support in California uses a complex algebraic formula — often called the "Dissomaster formula" after the software — that considers each parent's net disposable income (after taxes, mandatory deductions, and health insurance premiums) and the percentage of time each parent spends with the child.

The formula produces a statewide guideline amount that courts are required to follow absent specific statutory grounds for deviation. Trusted child support calculators for California use this formula — this estimator applies the same § 4055 factors.

• Factors in the California child support formula include: both parents' gross income
• allowable deductions (taxes using a simplified formula, mandatory union dues, health insurance premiums, and mandatory retirement contributions)
• the percentage of time each parent has physical custody
• and certain hardship deductions for extraordinary expenses or other children. California child support guidelines do not use a simple table — the algebraic formula produces different results for every combination of income and timeshare. The county child support agency (DCSS) in each California county enforces support orders and can assist custodial parents with establishing or modifying child support orders.