California Child Support Calculator
Calculate child support in California using the Income Shares model with SB 343 updates and K-factor formula for accurate estimates.
Understanding California Child Support
Income Shares Model
- Based on both parents' combined income
- Each parent pays proportional share
- Considers time-sharing arrangements
Recent Updates
- SB 343 legislative improvements
- Enhanced high-income calculations
- Updated guideline formulas
How California Child Support Works
1. Income Calculation (Family Code § 4058)
California considers all income sources including wages, self-employment, bonuses, rental income, and investments. Business expenses are scrutinized for legitimacy.
Key Point: Variable income (bonuses, commissions) must be averaged over 12 months when possible, following FL-150 form requirements.
2. K-Factor Formula Application
The K-factor combines time-sharing percentage with income levels to determine basic support. SB 343 (2024) updated these calculations for greater accuracy.
SB 343 Update: New income bands provide more precise calculations, especially for high-income families earning over $10,000/month.
3. Add-On Costs & Final Amount
Childcare, uninsured medical expenses, and special needs costs are added to basic support and allocated proportionally based on each parent's income percentage.
Important: Both parents must contribute to add-on costs based on their proportional share of total net disposable income.
Why Trust Our Calculator?
Legal Compliance
Implements exact Family Code § 4055 formulas with SB 343 updates. Results match court-approved software.
Current Guidelines
Updated with 2024 SB 343 changes including new income bands and K-factor calculations.
Professional Grade
Complex tax calculations, business expense handling, and variable income averaging built-in.
Calculate Your Child Support
Our calculator uses California's Income Shares model with current SB 343 guidelines and K-factor formulas for accurate estimates.
Important Legal Disclaimer
This calculator provides estimates based on California Family Code and current guidelines. Actual court orders may vary based on specific circumstances, extraordinary expenses, and judicial discretion. Consult with a qualified California family law attorney for advice specific to your situation.
Sample Calculation
Example: Two Parents, One Child
Parent A (Higher Earner)
- • Gross Income: $8,000/month
- • Net Disposable Income: $5,800/month
- • Time with child: 30%
Parent B (Lower Earner)
- • Gross Income: $4,000/month
- • Net Disposable Income: $3,200/month
- • Time with child: 70%
Calculation Steps:
Note: This example excludes add-on costs (childcare, medical). Actual calculations include comprehensive tax computations and all deductions.
Frequently Asked Questions
How accurate are these calculations?
Our calculator implements the exact Family Code § 4055 formulas with SB 343 updates. Results match court-approved software like DissoMaster when identical inputs are used. However, courts may deviate based on special circumstances.
What if I'm self-employed?
Self-employment income requires careful documentation. Include gross receipts and subtract only legitimate business expenses. Personal expenses disguised as business deductions will be added back to income by the court.
How does 50/50 custody affect support?
Equal time-sharing (50/50) doesn't eliminate child support. The higher-earning parent typically still pays support, but the amount is reduced due to the equal time factor in the K-factor formula.
When would a court deviate from guidelines?
Courts may deviate for extraordinary medical expenses, educational needs, significantly high income, or when guideline support would be unjust. Any deviation must be explained in writing with specific findings.
SB 343 Updates: What Changed in 2024
Enhanced K-Factor Calculations
SB 343 introduced refined income bands for K-factor determination, providing more accurate calculations especially for families with combined incomes above $10,000/month.
New Income Band Structure:
- • $0-$2,500: Basic percentage model (simplified)
- • $2,500-$7,500: Standard K-factor application
- • $7,500-$15,000: Enhanced precision factors
- • $15,000+: Discretionary high-income guidelines
Improved Add-On Cost Distribution
SB 343 clarified how childcare, medical, and educational costs are allocated between parents, ensuring proportional responsibility based on net disposable income ratios.
Enhanced Add-On Categories:
- • Childcare costs (work-related and education-related)
- • Uninsured medical expenses above $250/year
- • Special needs educational costs
- • Extraordinary extracurricular activities
- • Travel costs for visitation (case-specific)
Low-Income Protection Enhancements
The legislation strengthened protections for low-income families, ensuring basic living standards are maintained while fulfilling child support obligations.
Self-Support Reserve: Updated to $1,676/month (2024), ensuring paying parent retains minimum for basic living expenses after child support obligations.
Understanding the K-Factor Formula
Basic K-Factor Components
Time-Sharing Percentage (H)
- • H1: Higher earner's time with child
- • H2: Lower earner's time with child
- • Must total 100% (H1 + H2 = 100%)
- • Includes overnight stays and day visits
Income Ratio Factors
- • Combined family NDI considered
- • Income band determines multipliers
- • Regional cost adjustments may apply
- • Extraordinary income provisions
Step-by-Step K-Factor Calculation
Determine Time-Share Percentages
Calculate actual time each parent spends with child, including overnights and day visits.
Calculate Combined Net Disposable Income
Sum both parents' NDI after all allowable deductions (taxes, mandatory retirement, health insurance).
Apply Income Band Multipliers
Use SB 343 income bands to determine appropriate K-factor range for family's income level.
Calculate Final K-Factor
Combine time-share and income factors using the official California guideline formula.
Common Calculation Errors to Avoid
❌ Error #1: Incorrect Income Categorization
Common Mistake: Excluding irregular income like bonuses or overtime
Correct Approach: Include all income sources and average variable income over 12 months when possible.
California courts require inclusion of all income sources. Attempting to hide or minimize irregular income often backfires and can damage credibility.
⚠️ Error #2: Business Expense Manipulation
Common Mistake: Claiming excessive business deductions to reduce net income
Correct Approach: Only legitimate, necessary business expenses are allowed. Personal expenses disguised as business costs will be added back.
Courts scrutinize self-employed parents' deductions carefully. Document all business expenses with receipts and ensure they serve legitimate business purposes.
⚠️ Error #3: Time-Share Miscalculation
Common Mistake: Only counting overnight visits or ignoring day visits
Correct Approach: Include all time child spends with each parent, including day visits, school pickups, and extended weekend time.
Even a few hours difference in time-share calculation can significantly impact support amounts. Keep detailed records of actual time spent with children.
⚠️ Error #4: Ignoring Add-On Cost Proportionality
Common Mistake: Assuming 50/50 split of add-on costs regardless of income
Correct Approach: Add-on costs must be allocated proportionally based on each parent's percentage of total NDI.
A parent earning 70% of combined income typically pays 70% of add-on costs, not 50%. This proportional allocation is required under California law.
California vs Other State Models
| State | Model | Key Features | Complexity |
|---|---|---|---|
| California | Income Shares | K-factor formula, combined income analysis, time-sharing integration | High |
| Texas | Percentage of Income | Simple percentage of noncustodial parent's net income | Low |
| Florida | Income Shares | Income shares with time-sharing adjustments, no K-factor | Medium |
| New York | Income Shares | Combined income approach with statutory percentages | Medium |
Why California's Model is More Complex
California's Income Shares model with K-factor calculations requires consideration of both parents' incomes, time-sharing arrangements, and complex income band analysis. While more accurate in theory, it requires sophisticated calculation tools and detailed financial documentation.
Related Resources
Understand the legal framework behind your calculations
Read Law GuideCalculate your other California support obligations
Calculate NowWhy California's Model is More Complex
California's Income Shares model with K-factor calculations requires consideration of both parents' incomes, time-sharing arrangements, and complex income band analysis. While more accurate in theory, it requires sophisticated calculation tools and detailed financial documentation.