California child support calculator
Enter both parents' monthly income, the number of children and your share of time with them. See the estimate under California's guideline formula, step by step.
- California's own formula, CS = K[HN − (H%)(TN)], from Family Code section 4055.
- Both incomes and time-share count: more time with the children lowers what a parent pays.
- 2026 low-income adjustment for paying parents with net income under $2,929 a month.
How California calculates child support
California uses its own formula, written into Family Code section 4055: CS = K[HN − (H%)(TN)]. HN is the higher earner's net disposable income, TN is both parents' total, and H% is the higher earner's share of time with the children. K is the share of the parents' combined income that goes to child support.
If the result is positive, the higher earner pays it. If it's negative, which can happen when the higher earner has most of the time, the lower earner pays (§4055(b)(5)). For more than one child, the one-child amount is multiplied: 1.6 for two children, 2 for three, up to 2.86 for ten.
| Total net income (TN) per month | K fraction (§4055(b)(3)) |
|---|---|
| $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 |
Example: $6,000 and $4,000 net, 20% time-share
This is the Judicial Council's own example from its 2025 guideline review (Invitation to Comment SP26-01). The higher earner has net disposable income of $6,000 a month and the children 20% of the time; the other parent has $4,000.
| TN: $6,000 + $4,000 | $10,000 |
|---|---|
| K fraction for TN of $10,000 | 0.25 |
| K: 0.25 × (1 + 20%) | 0.30 |
| HN − H% × TN: $6,000 − 20% × $10,000 | $4,000 |
| Child support for one child: 0.30 × $4,000 | $1,200 |
With two children the amount is $1,200 × 1.6 = $1,920; with three, $2,400. Choose "Net disposable" in the calculator and enter $6,000, $4,000 and 20% to see the same steps.
Net disposable income and the extras
The formula uses each parent's net disposable income: gross income minus state and federal income tax actually owed, Social Security and Medicare, State Disability Insurance, mandatory union dues and retirement, health insurance premiums, and court-ordered child or spousal support paid for others (§4059). A court can also allow deductions for job-related expenses and hardship.
Child care for work or job training and the children's reasonable uninsured health costs are added on top of the formula amount. Since September 1, 2024, they are split in proportion to the parents' net incomes, with the paying parent's income reduced by the basic support they pay, unless the court orders another split (§4061, §4062).
| Low-income adjustment | If the paying parent's net disposable income is below full-time minimum wage ($2,929 a month in 2026), support is presumed to be reduced by up to the amount × (2,929 − net) ÷ 2,929. The court can find that unjust in a particular case (§4055(b)(7)). |
|---|---|
| Varying from the formula | The formula amount is presumed correct. A court can order a different amount for reasons listed in §4057(b), such as an extraordinarily high income or special needs of the children, and must explain why. |
| A new spouse's income | Generally not considered, except in extraordinary cases (§4057.5). |
Questions people ask
How is child support calculated in California?
California uses the formula in Family Code section 4055: CS = K[HN − (H%)(TN)]. It takes both parents' monthly net disposable incomes and the higher earner's percentage of time with the children. K depends on the parents' total net income and the time-share. For more than one child, the result is multiplied, for example by 1.6 for two children.
How much is child support in California for one child?
It depends on both incomes and the time-share. In the Judicial Council's example, a parent with $6,000 a month net and 20% of the time, and another parent with $4,000, give $1,200 a month for one child. The same family with the higher earner at 40% of the time would give 0.25 × 1.4 × ($6,000 − 40% × $10,000) = $700.
What is the official California child support calculator?
The California Department of Child Support Services publishes the official Guideline Calculator at childsupport.ca.gov. Courts use it or other calculators certified by the Judicial Council. Our calculator follows the same statute but estimates taxes more simply, so the official tool can give a different number.
What is the low-income adjustment in 2026?
When the paying parent's net disposable income is less than the gross income from full-time work at California's minimum wage, $2,929 a month in 2026 ($16.90 an hour), the law presumes a reduced amount. The most it can be reduced is the support amount times (2,929 minus the parent's net income) divided by 2,929, and the lowest amount in that range is presumed correct.
Does 50/50 custody mean no child support in California?
No. With equal time, the formula still produces support when incomes differ: at H% of 50%, CS = K × (HN − 50% × TN), which is positive whenever the higher earner earns more than the other parent. Support is zero only when each parent's share of income matches their share of time.
How are child care costs split in California?
Since September 1, 2024, child care for work or job training and the children's uninsured health costs are split in proportion to the parents' net disposable incomes, with the paying parent's income first reduced by the basic support they pay. Before that the default was 50/50. A court can order a different split (§4061).
Updated November 8, 2026. Sources: Cal. Fam. Code §4055 (operative September 1, 2024, Stats. 2023, ch. 213), §§4057, 4057.5, 4059, 4061, 4062; Judicial Council, LIA threshold table (2026: $2,929); Judicial Council, Invitation to Comment SP26-01 (worked examples); FTB Tax News, October 2026 (2026 California tax rates); EDD (2026 SDI rate 1.3%); IRS Rev. Proc. 2025-32. An estimate, not legal advice: the court or the local child support agency sets the actual amount. Not affiliated with DCSS, the Judicial Council or any California court.