California Workers' Compensation Insurance Cost
California workers' compensation cost is primarily calculated as payroll per $100 multiplied by the class-code rate, then adjusted by the experience modification and other underwriting factors. Costs vary widely by industry, payroll, claims history, and carrier.
Key Takeaways
- Premium = (Payroll ÷ 100) × Rate × Experience Mod, plus other factors.
- High-hazard industries carry much higher base rates.
- The experience mod can raise or lower premium significantly.
- Safety and return-to-work programs are the biggest long-term cost reducers.
What Determines Cost
Three factors drive most of the cost: payroll, the class-code rate, and the experience modification. Additional factors—credits, debits, minimum premiums, assessments, and expenses—also apply.
The Basic Formula
Estimated Base Premium = Payroll ÷ 100 × Rate. Estimated Modified Premium = Base Premium × Experience Modification Factor. This is an estimate only; actual premium depends on carrier underwriting and other rating factors.
How to Lower Your Premium
Reduce claims with safety and return-to-work programs, verify correct class codes, manage payroll reporting, improve your experience mod, and shop the market with a broker. Use the estimator on this page for an educational estimate.
Frequently Asked Questions
Experience Modification & Cost
Understanding Your Experience Modification
The experience modification (x-mod) is a factor calculated by the WCIRB that adjusts your workers' comp premium based on your claims history versus similar businesses.
Generally indicates better-than-average claims experience. This typically lowers your premium and may unlock preferred carrier programs.
Generally indicates worse-than-average claims experience. This typically raises your premium and may limit some carrier options.
Why claims history matters: Both the frequency and severity of claims influence the mod. Medical-only claims have a reduced impact compared to indemnity (wage-loss) claims.
How it affects premium: The mod multiplies your base premium, so on high-hazard class codes it has a large dollar effect.
We do not calculate an official experience modification—that requires official WCIRB rating data.
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