California Child Support Calculator (2026)

How California calculates child support

California does not use a basic support table like most states. Family Code Section 4055 sets a single formula that combines both parents’ net disposable income and the higher earner’s timeshare. The formula is:

CS = K[HN − (H%)(TN)]

HN is the higher earner’s net monthly disposable income. TN is the combined net monthly disposable income of both parents. H% is the approximate percentage of time the higher earner has primary physical responsibility for the children. K is a factor that depends on TN and H%, and it is the part that changed when the K table was revised in 2024.

The formula produces a positive number when the higher earner should pay the lower earner. If the result is negative, the lower earner pays the higher earner the absolute value. At an equal timeshare, the result can still be positive if one parent has significantly more income.

The K-factor in 2026

Under the current formula, the K-factor starts with a bracket amount based on TN:

The bracket amount is then multiplied by (1 + H%) when H% is 50% or less, or by (2 − H%) when H% is above 50%. That second step is why the formula is not a simple “percentage of income” calculation. The timeshare and the income bracket interact.

Net disposable income, not gross pay

California uses net disposable income under Section 4059. Starting from gross income, the statute allows deductions for federal and state income taxes, Social Security, Medicare, mandatory retirement contributions, health insurance premiums, union dues, and other required deductions. The goal is to measure what each parent actually has available for the child, not what the paycheck says before withholding.

The form asks for net disposable income directly. If you only know gross pay, the estimate will be too high. Use a recent pay stub, the official California Guideline Calculator, or a tax return to get to the net figure. For a self-employed parent, the deduction analysis is more complex and often needs an attorney or forensic accountant.

Timeshare and the multi-child multiplier

H% is based on the higher earner’s overnights, not the lower earner’s. If the higher earner has the children 20% of the time, H% is 20%. At 50/50, H% is 50%. If the higher earner has the children most of the time, H% can be above 50%, and the formula can reverse who pays.

For more than one child, California multiplies the one-child result by a statutory factor: 1.6 for two children, 2 for three, 2.3 for four, 2.5 for five, 2.625 for six, 2.75 for seven, 2.813 for eight, 2.844 for nine, and 2.86 for ten. The factor is not a per-child add-on; it reflects the economies of scale in raising siblings.

A California example at 20% timeshare

Take Parent A with $6,000 of net disposable income, Parent B with $3,000, one child, and a 20% timeshare for Parent A. TN is $9,000, so the bracket amount is 0.250. H% is 20%, so K is (1 + 0.20) × 0.250 = 0.300. The formula gives 0.300 × ($6,000 − 0.20 × $9,000) = $1,260 per month.

With two children, the same inputs produce $1,260 × 1.6 = $2,016 per month. The arithmetic assumes no add-ons, no low-income adjustment, and no deviation; it illustrates the formula, not a judge’s decision.

What the California estimate leaves out

• Childcare, uninsured health costs, and travel add-ons under Section 4062.
• The low-income adjustment under Section 4055(b)(7).
• Hardship deductions for children from another relationship.
• Temporary spousal support, which some counties calculate with a local formula.
• Deviations for special needs, extraordinary expenses, or a parent’s unusual circumstances.
• Past-due support, interest, and any credit for benefits paid to the child.

The formula also assumes that the incomes you enter are the incomes the court will accept. If a parent is self-employed, has stock compensation, owns a business, or is intentionally underemployed, the court can adjust income before applying the formula. That deduction can move the result more than the formula itself.

When California’s guideline calculator is the better choice

California’s Department of Child Support Services publishes the official guideline calculator. It walks through the Section 4059 deductions, the low-income adjustment, and the add-ons, and it produces a worksheet that courts and county agencies recognize. Use it if you need a filing-ready calculation or if either parent has income that is hard to characterize.

A family law attorney is the right next step if the parents disagree about timeshare, if one parent is in another state, or if the case involves a business, stock options, or a request to deviate. The calculator is a way to understand the moving parts, not a substitute for that review.

Frequently asked questions