California Child Support Calculator (2026)

California uses one statewide formula that weighs both parents' net disposable income and the share of time each parent has the children. Enter both incomes and the timeshare to see the guideline amount, the K factor, and who pays.

Figures reviewed September 29, 20265 primary sources

Estimated monthly child support

$880per month

Parent A pays Parent B.

Per year: $10,560

How we got there

Parent A net disposable income	$4,673
Parent B net disposable income	$2,896
Higher earner (Parent A) share of parenting time	20%
Income fraction for combined net income	0.232
K factor	0.279
Guideline for one child	$880
Basic guideline child support	$880

Net disposable income is estimated for a single filer with federal tax, California tax, Social Security, Medicare and SDI withheld. Courts use certified software with each parent's actual filing status.
The low-income adjustment in section 4055(b)(7) and any hardship deductions are not applied in this estimate.

Standing assumptions

Formula from Family Code section 4055; multiple-child factors from section 4055(b)(4).
Taxes estimated with 2026 federal brackets and the latest published California brackets, single filing status.
Mandatory add-ons are split equally under section 4061 unless a court orders otherwise.

Estimate only. Not legal advice.

Key 2026 numbers for California

Guideline formula: CS = K[HN - (H%)(TN)]; Family Code section 4055. HN is the higher earner's net income, TN both parents' combined net income.
Two children: x 1.6; Three children x 2, four x 2.3, five x 2.5, up to ten children x 2.86.
Add-ons: Split 50/50; Work-related childcare and uninsured health costs, unless the court orders an income-based split.
Ends at: 18 or 19; Age 18, or 19 if the child is still a full-time high school student living at home.

How the California guideline formula works

Family Code section 4055 sets child support with an algebraic formula: CS = K[HN - (H%)(TN)]. HN is the higher earner's net monthly disposable income, TN is both parents' combined net disposable income, and H% is the approximate percentage of time the higher earner has primary physical responsibility for the children. K is a multiplier that depends on combined income and timeshare.

K equals (1 + H%) times an income fraction when the higher earner has the children half the time or less, and (2 - H%) times the fraction when the higher earner has them more than half the time. The fraction is 0.20 plus TN/16,000 for combined net income up to $800, 0.25 up to $6,666, 0.10 plus 1,000/TN up to $10,000, and 0.12 plus 800/TN above that.

If the result is positive, the higher earner pays it to the lower earner. If it is negative, which happens when the higher earner has most of the parenting time, the lower earner pays the absolute value to the higher earner. For more than one child, the one-child result is multiplied by the factors in section 4055(b)(4).

Net disposable income

Section 4058 counts income from all sources: wages, commissions, bonuses, self-employment, rents, interest, pensions, disability, unemployment and workers' compensation. Section 4059 then deducts state and federal income tax based on the parent's actual filing status, FICA, mandatory union dues and retirement contributions, health insurance premiums, child or spousal support actually paid under other orders, and approved hardship deductions.

Courts run the numbers through certified guideline software, and the Department of Child Support Services offers a free online calculator. This estimate models a single filer with standard deductions, so parents who file as head of household or itemize will see somewhat different net income.

Timeshare

Timeshare is the fraction of the year each parent has physical responsibility for the children, usually counted from the custody schedule in overnights plus long non-overnight periods. A parent with alternating weekends and one weeknight dinner is around 20%; a week-on, week-off schedule is 50%. Small changes in timeshare can move the result noticeably, so use a realistic count.

Add-ons and hardship deductions

Section 4062 requires two mandatory add-ons on top of guideline support: childcare needed for work or job training, and uninsured health care costs for the children. The court may also add costs of the children's education or special needs and travel for visitation. Under section 4061 add-ons are shared equally unless a parent asks for a split proportional to net disposable income.

Section 4071 allows a hardship deduction for extraordinary health expenses, uninsured catastrophic losses, and the basic living expenses of the parent's other children who live with them.

Deviating from the guideline

The formula amount is presumptively correct under section 4057, but a court may order a different amount if the parents stipulate to it, the paying parent has an extraordinarily high income, one parent is not contributing to the children's needs in proportion to their custodial time, or applying the formula would be unjust in a specific case. The court must state the guideline amount and its reasons for deviating.

A low-income adjustment under section 4055(b)(7) can reduce support when the paying parent's net disposable income falls below a threshold that the Judicial Council adjusts each year. This estimate does not apply that adjustment.

Duration and modification

Support normally continues until the child turns 18, or 19 if the child is still a full-time high school student living with a parent (section 3901). Either parent can request a modification when circumstances change, such as a new job, a change in the custody schedule, or the birth of another child. Courts can also add a Gavron-style warning, but child support itself is not reduced simply because the receiving parent could earn more, unless income is imputed.

Worked example

Parent A has $5,000 in net disposable income per month; Parent B has $1,500. Combined net income (TN) is $6,500, so the income fraction is 0.25.
The children spend 20% of their time with Parent A, the higher earner, so H% is 0.20 and K = (1 + 0.20) x 0.25 = 0.30.
CS = 0.30 x ($5,000 - 0.20 x $6,500) = 0.30 x $3,700 = $1,110 for one child.
With two children the amount is $1,110 x 1.6 = $1,776.

Parent A pays Parent B $1,110 per month for one child, before add-ons.

California child support questions

How does 50/50 custody affect child support in California?

Equal time does not automatically mean zero support. With H% at 50%, the formula still transfers money from the higher earner to the lower earner in proportion to the income gap. Support reaches zero only when both incomes are also roughly equal.

Does my new spouse's income count?

Generally no. Section 4057.5 excludes a new spouse's or partner's income except in extraordinary cases where excluding it would cause extreme hardship to the child. It can still affect the parent's tax filing status and therefore net income.

Can income be imputed to a parent who is not working?

Yes. Under section 4058(b) the court may use a parent's earning capacity instead of actual income when that is consistent with the child's best interest, considering the parent's ability and opportunity to work.

Is the guideline amount mandatory?

It is presumed correct. Courts can approve a different agreed amount if both parents are informed of their rights, no one is on public assistance, and the agreement serves the children's interests. Otherwise the court needs findings under section 4057 to deviate.

Where is the official California calculator?

The California Department of Child Support Services publishes the official Guideline Calculator, which mirrors the certified software courts use. Use it to confirm the estimate here with your exact tax settings.

Sources

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