⚖️ California Child Support Calculator 2026 – Free CA Guideline Estimate (SB 343 Updated)
Estimate your California child support obligation using the official guideline formula under Family Code §4055, updated for SB 343 (effective September 2025). Works for Los Angeles, San Diego, San Francisco, Sacramento, and all California counties. Free, fast, step-by-step breakdown shown.
Convert annual or weekly income to monthly gross, then estimate California net disposable income (NDI) used in the child support formula.
Estimate whether your current child support order may increase or decrease based on income or custody changes.
California Child Support Calculator 2026 — Complete Guide
Whether you're a parent navigating divorce, a co-parent seeking a modification, or someone trying to understand what to expect before court, our free California child support calculator gives you a realistic, formula-based estimate using the official California guideline under Family Code §4055. This tool is fully updated for the SB 343 changes effective September 2025 — the most significant overhaul to California's child support formula since 1992.
Unlike simple percentage-based tools, California uses a complex algebraic formula that factors in both parents' net incomes, custody time percentages, number of children, and mandatory add-on expenses. Our free child support calculator applies this same logic step by step, shows you exactly how the number is reached, and explains what factors could change it — all in plain English.
The California Child Support Formula Explained — CS = K[HN – (H%)(TN)]
California courts do not use a simple percentage of income table. Instead, they apply a specific algebraic formula under California Family Code §4055 that accounts for both parents' financial situations and time spent with the children. Here is exactly how the formula works:
CS = K × [HN – (H%) × (TN)]
CS = Monthly child support amount (for one child)
K = Income allocation factor (K-factor) — percentage of combined net income allocated to child support, based on income band
HN = Net monthly disposable income of the higher-earning parent
H% = Percentage of time the higher-earning parent has physical custody
TN = Combined total net monthly disposable income of both parents
For multiple children: Multiply the one-child result by the statutory multiplier:
2 children = ×1.6 | 3 children = ×2.0 | 4 children = ×2.3 | 5 children = ×2.5
What Is the K-Factor in California Child Support?
The K-factor is the percentage of the parents' combined net income that California law designates for child support. Under the SB 343 update effective September 2025, the K-factor bands were significantly revised. The K-factor varies based on the total combined net monthly disposable income (TN) of both parents:
| Combined Net Monthly Income (TN) | K-Factor (1 Child) | Notes |
|---|---|---|
| $0 – $2,929/month | 0.20 (20%) | Low-income adjustment band (SB 343 updated) |
| $2,930 – $6,500/month | 0.25 (25%) | Highest K-factor — most common income range |
| $6,501 – $10,000/month | 0.22 (22%) | Upper-middle income |
| $10,001 – $15,000/month | 0.19 (19%) | Higher income band |
| $15,001 – $25,000/month | 0.16 (16%) | High income |
| Above $25,000/month | 0.12 (12%) | Very high income (court may deviate) |
*K-factor bands are approximate post-SB 343 estimates based on available legislative data. Actual certified calculator values may vary slightly. Consult a California family law attorney for precise figures.
How to Calculate Net Disposable Income (NDI) in California
The California child support formula uses Net Disposable Income (NDI) — not gross income — for both parents. NDI is calculated by taking gross income and subtracting specific allowable deductions. Since SB 343, this calculation now explicitly uses net income as the basis for K-factor assignment as well.
NDI = Gross Income
− Federal income tax (based on filing status)
− California state income tax (SDI included)
− FICA / Social Security (6.2%) and Medicare (1.45%)
− Health insurance premiums (for children)
− Mandatory union dues
− Existing court-ordered child/spousal support payments
− Hardship deductions (if applicable)
Example: Gross $6,667/month (Single filer):
Federal tax ≈ $840 | CA state tax ≈ $430 | FICA ≈ $510
NDI ≈ $6,667 − $840 − $430 − $510 = ≈ $4,887/month
Common Income Scenarios — How Much Child Support Will I Pay in California?
One of the most frequently searched questions is understanding what a specific salary translates to in California child support. The amount depends on three key variables: your income, the other parent's income, and custody time. Here are real-world estimates for common scenarios using the California guideline formula (assuming you are the higher earner, other parent earns $3,000/month gross, and you have 20% custody time):
| Your Annual Income | Monthly Gross | Est. NDI/Month | Est. Child Support (1 child, 20% custody) | Per Year |
|---|---|---|---|---|
| $52,000/yr ($1,000/wk) | $4,333 | ~$3,200 | $450 – $620/month | ~$6,300 |
| $60,000/yr | $5,000 | ~$3,700 | $520 – $720/month | ~$7,500 |
| $80,000/yr | $6,667 | ~$4,850 | $680 – $950/month | ~$9,800 |
| $100,000/yr | $8,333 | ~$5,900 | $850 – $1,150/month | ~$12,000 |
| $120,000/yr | $10,000 | ~$6,900 | $950 – $1,300/month | ~$13,800 |
| $150,000/yr | $12,500 | ~$8,400 | $1,100 – $1,500/month | ~$15,600 |
*Estimates assume: other parent earns $3,000/month gross, single tax filer, 20% custody for paying parent, 1 child, no add-ons. Actual amounts depend on your specific situation. Use the calculator above for your numbers.
If I Make $1,000 a Week How Much Child Support Do I Pay in California?
$1,000 a week = $4,333/month gross. After California state tax, federal income tax, and FICA deductions for a single filer, your net disposable income (NDI) is approximately $3,100–$3,300/month. If the other parent earns around $2,500–$3,000/month gross and you have 20% custody time, the California guideline formula estimates child support at approximately $450–$650/month for one child. For two children, multiply by 1.6 — approximately $720–$1,040/month. Enter your exact figures into the calculator above for a personalized estimate.
If I Make $80,000 a Year How Much Child Support Do I Pay?
$80,000 a year = $6,667/month gross. Net disposable income after taxes is roughly $4,800–$5,100/month for a single filer in California. With the other parent earning $3,000/month and you having 20% physical custody, the California guideline child support estimate is approximately $680–$950/month per child. If you have 50/50 custody, the amount drops significantly — sometimes to $0 if both parents earn similar incomes.
If I Make $60,000 a Year How Much Child Support Do I Pay?
$60,000 a year = $5,000/month gross. California NDI after taxes for a single filer is approximately $3,600–$3,900/month. California guideline child support with 20% custody and the other parent earning $2,500/month is estimated at $520–$720/month for one child. Custody time is the single biggest variable — even moving from 20% to 35% custody can reduce the monthly amount by $150–$300.
If I Make $100,000 a Year How Much Child Support Do I Pay?
$100,000 a year = $8,333/month gross. After California state and federal taxes as a single filer, NDI is approximately $5,800–$6,300/month. With 20% custody and the other parent earning $3,000/month, California guideline child support for one child is approximately $850–$1,150/month. For higher earners, courts retain discretion to deviate from the guideline when the formula amount would exceed the children's reasonable needs.
Custody Time and Its Impact on California Child Support
California's formula is unique among U.S. states in how heavily it weights custody time (timeshare). Because H% appears in the formula, even small changes in custodial time can produce significant changes in the support amount. Here is how custody percentages translate to real time:
| Custody Arrangement | Approx. % Time (H%) | Nights/Year | Support Impact |
|---|---|---|---|
| Every other weekend only | 14% | 52 | Higher support owed |
| Every other weekend + one weeknight | 20% | 73 | Standard baseline |
| Every other weekend + extended summers | 28% | 102 | Moderate reduction |
| Week-on / week-off (50/50) | 50% | 182 | Significant reduction |
| Primary custody (you have child most) | 65%+ | 237+ | You likely receive support |
In a 50/50 custody arrangement where both parents earn similar incomes, California child support can be $0 or near $0 because the formula's (H%)(TN) term nearly cancels out the HN term. This is one of the most important things to understand about the California system — spending more time with your children directly reduces the support amount you owe.
Mandatory Add-On Expenses in California Child Support
The base child support figure produced by the CS formula is not the final number. California law under Family Code §4061-4062 requires courts to add on certain mandatory expenses, which are shared between parents proportionally to their net incomes (post-SB 343 — previously split 50/50):
- Childcare costs: Work-related or job-training childcare is mandatory add-on. Split proportionally to each parent's NDI.
- Uninsured medical and dental expenses: Out-of-pocket medical, dental, and vision costs exceeding $250/year per child are split proportionally.
- Health insurance premiums: The cost of adding children to a parent's health plan is typically credited to the paying parent's deductions and may be added on separately.
- Educational or special needs costs: Private school tuition, therapy, special education costs — courts may order these as add-ons by agreement or evidence of need.
- Travel for visitation: Where parents live far apart, extraordinary transportation costs may be ordered as an add-on by the court.
San Diego Child Support Calculator — County-Specific Notes
Whether you're in San Diego, Los Angeles, Orange County, Riverside, Sacramento, or any other California county, the same statewide guideline formula under Family Code §4055 applies. California has one uniform child support law — there is no county-specific formula. The San Diego child support calculator result will be identical to the Los Angeles or Fresno result for the same income and custody inputs.
However, local factors can affect the outcome: San Diego Family Court has local rules about how income is documented, and the county's DCSS (Department of Child Support Services) office at childsupport.ca.gov provides the official free online calculator. Our tool provides an estimate using the same formula for educational reference — for a certified result, use the official DCSS Guideline Calculator or consult a San Diego family law attorney.
How to Modify a California Child Support Order
California child support orders are not permanent. Either parent can request a modification when there has been a material change in circumstances. Common grounds for modification include:
- Income change: Job loss, significant raise, new employment, or disability affecting earning capacity.
- Custody change: A change in the actual amount of time each parent spends with the child.
- New children: A parent having additional children can affect the K-factor calculation.
- Change in expenses: Significant increase or decrease in childcare, health insurance, or medical costs.
- Child's changed needs: New educational requirements, medical conditions, or other expenses.
Use the Modification Estimator tab in the calculator above to get a rough sense of whether a modification might increase or decrease support based on income or custody changes. For an actual modification, you must file a Request for Order (RFO) with the court or contact your county's DCSS office.
Frequently Asked Questions — California Child Support Calculator
Q: How accurate is this California child support calculator?
A: Our easy CA child support calculator uses the official Family Code §4055 formula with SB 343 K-factor updates. It is designed to produce a realistic estimate — typically within 10–15% of what certified software would produce. Tax calculations are simplified approximations. For exact amounts, use the official DCSS Guideline Calculator at childsupport.ca.gov or consult a California family law attorney.
Q: Is the California child support formula the same in 2026 as 2025?
A: The core formula (CS = K[HN – (H%)(TN)]) remains the same. The significant update was the SB 343 change effective September 1, 2025, which revised K-factor bands to use net income, raised the low-income adjustment threshold to $2,929/month in 2026, and changed add-on expense allocation. Our CA child support calculator 2026 reflects these updates.
Q: What happens if I refuse to pay California child support?
A: Non-payment of court-ordered child support in California has serious consequences: wage garnishment (up to 65% of disposable income), bank account levies, California driver's license suspension, professional license suspension, passport denial, contempt of court charges, and credit reporting. California DCSS actively enforces support orders through income withholding.
Q: Can parents agree to a different amount than the California guideline?
A: Yes, parents can stipulate to a different amount — but the court must approve it. Both parents must knowingly waive their right to guideline support, and the agreed amount must meet the children's basic needs. Courts are reluctant to approve below-guideline agreements unless both parents have independent legal advice.
Q: Does California child support end at 18?
A: Generally yes — child support ends when the child turns 18, or 19 if the child is still a full-time high school student. Parents can agree to extend support for college or other purposes. Special needs children may receive support beyond these ages by court order.
Q: Is this calculator the same as the DCSS online calculator?
A: Our tool is a free educational estimator that applies the same California guideline formula. The official DCSS Guideline Calculator at childsupport.ca.gov/guideline-calculator is the state-certified version used in court proceedings. We recommend using both for comparison, and consulting an attorney for your specific case.
Use our free California child support calculator above to get an instant estimate with full step-by-step breakdown. Updated for 2026 SB 343 guidelines. For Los Angeles, San Diego, San Francisco, Sacramento, and all California counties. Not legal advice — always confirm with a licensed California family law attorney.