California Child Support Calculator
Estimate California guideline child support using the statewide CS = K x (HN - H% x TN) formula. Enter each parent's net income, timeshare and number of children.
Updated 2026-06-14 · Free · No sign-up · Runs privately in your browser
"Net monthly income" = monthly disposable income after taxes and mandatory deductions. Timeshare is the percentage of parenting time the higher earner spends with the children.
Show the formula & steps
Estimate based on California's statewide guideline (Family Code §4055) using a 2024 snapshot of the K-factor schedule. The court has discretion; official figures come from the DissoMaster / state Guideline Calculator with full tax and deduction detail — verify your county's current guidelines. Not legal or financial advice.
How it works
The California Child Support Calculator estimates guideline support under Family Code section 4055, the statewide formula every court starts from. You enter each parent’s net monthly income, the higher earner’s timeshare with the children, and the number of children. It returns the income-allocation factor (K), which parent pays, and the estimated monthly support.
Estimate based on California’s statewide guideline using a 2024 snapshot of the K-factor schedule. The court has discretion, and official figures come from the DissoMaster / state Guideline Calculator with full tax and deduction detail — verify your county’s current guidelines. This is not legal or financial advice.
The guideline formula
California’s base, one-child formula is:
CS = K x (HN − (H% x TN))
where:
- TN = combined net monthly disposable income of both parents
- HN = net monthly disposable income of the higher earner
- H% = the higher earner’s share of physical responsibility (parenting time)
- K = an income-allocation factor from the section 4055(b)(3) schedule
The K factor is built from a base fraction that depends on combined income TN:
| Combined net income (TN, per month) | Base fraction |
|---|---|
| Up to $801 | 0.20 + TN/16,000 |
| $801 – $6,666 | 0.25 |
| $6,666 – $10,000 | 0.10 + 1,000/TN |
| Over $10,000 | 0.12 + 800/TN |
When the higher earner’s timeshare is 50% or less, K = base fraction x 2. When it is above 50%, K = base fraction x (1 + 2 x (1 − H%)).
Multiple children
The formula gives the amount for one child. For more children, multiply by the statutory factor:
| Children | Multiplier |
|---|---|
| 1 | 1.0 |
| 2 | 1.6 |
| 3 | 2.0 |
| 4 | 2.3 |
| 5 | 2.5 |
| 6 | 2.625 |
Worked example
Parent A nets $5,000/month, Parent B nets $3,000/month, Parent A (the higher earner) has the children 20% of the time, and there is 1 child:
- TN = 5,000 + 3,000 = $8,000; HN = $5,000; H% = 0.20.
- TN is in the $6,666–$10,000 band, so the base fraction = 0.10 + 1,000/8,000 = 0.225. Since H% ≤ 0.50, K = 0.225 x 2 = 0.45.
- CS = 0.45 x (5,000 − 0.20 x 8,000) = 0.45 x (5,000 − 1,600) = 0.45 x 3,400 ≈ $1,530/month, paid by Parent A to Parent B.
Limitations
This calculator models the core section 4055 formula only. The official California guideline additionally accounts for tax filing status, mandatory retirement and union dues, health-insurance premiums, child-care costs and other add-ons through certified software such as DissoMaster. Judges may also deviate from guideline in specific circumstances. Treat the result as a starting estimate, not a court order.
Frequently asked questions
How is child support calculated in California?+
California uses a statewide guideline formula in Family Code section 4055: CS = K x (HN - H% x TN). TN is the combined net monthly disposable income of both parents, HN is the higher earner's net income, H% is the higher earner's share of parenting time, and K is an income-allocation factor from a published schedule. For more than one child the result is multiplied by a statutory factor.
What is the K factor in California child support?+
K is the fraction of combined income allocated to child support. It depends on the parents' combined net monthly income and the higher earner's timeshare. For middle incomes the base fraction is around 0.25 and K is roughly 0.5; the schedule rises for very low incomes and tapers for high incomes, and it increases when the higher earner has less than half the parenting time.
Does timeshare affect child support in California?+
Yes, heavily. H% in the formula is the higher earner's percentage of parenting time. The more time the higher earner spends with the children, the lower the guideline support they pay, because more of their income is presumed spent directly on the children. A 50/50 timeshare with equal incomes produces little or no guideline support.
How much is child support for two children in California?+
California first computes the one-child guideline amount, then multiplies it by a statutory factor: 1.6 for two children, 2.0 for three, 2.3 for four, 2.5 for five and so on. So two children is 1.6 times the one-child figure, not double.
Is this calculator the official California child support amount?+
No. This is an estimate. The official guideline uses the DissoMaster or state Guideline Calculator, which model tax filing status, deductions, health-insurance premiums, child-care and other add-ons in detail. A judge also has discretion to deviate. Use this tool for a ballpark figure and confirm with the court or an attorney.