Rate Methodology & Data Sources
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Every rate on WorkersCompCost.com is a modeled base-rate estimate — a transparent benchmark built from public regulatory filings, not a filed manual rate for any specific carrier and not a quote. This page documents exactly how those estimates are produced so you can judge their fitness for your purpose.
The short version
We start from a published per-class-code base rate per $100 of payroll, then scale it by a per-state index that reflects how expensive workers' comp is in that jurisdiction relative to a national baseline. The result is a like-for-like rate you can compare across all 50 states and the District of Columbia for the same class code.
How a rate is calculated
The estimated rate shown for a state × class-code pair is:
rate per $100 = base rate (class code) × state index
Worked example — NCCI class code 9082 (Restaurant NOC):
- Base rate for 9082: $3.75 per $100 of payroll
- Kentucky (state index 1.00, our baseline reference): 3.75 × 1.00 = $3.75
- New York (state index 1.45): 3.75 × 1.45 = $5.44
- Indiana (state index 0.78): 3.75 × 0.78 = $2.93
To turn a per-$100 rate into an annual premium estimate, the same formula the rate calculator uses applies:
annual premium ≈ (annual payroll ÷ 100) × rate × experience modifier
The experience modifier defaults to 1.00. Your bureau-published mod, carrier deviations, schedule credits, minimum premiums, and state assessments are not reflected in this benchmark.
How well calibrated these estimates are — measured, August 2026
We think a methodology page should publish the accuracy of its own model, including when that is unflattering. On 2 August 2026 we compared the figures this site derives against the only two state-regulator loss-cost publications we could retrieve. The result: our per-$100 figures are not calibrated to filed state loss costs, and they are typically too high.
- Georgia — against the advisory loss costs the Georgia State Board of Workers' Compensation publishes per class code, across the 170 codes we have in common: our figure was a median 2.3 times the filed loss cost. Only 10% of codes landed within 25% of the filed value, and 58% were more than double it.
- Texas — the Texas Department of Insurance publishes a 1 July 2026 loss cost for code 5551 (Roofing) of 1.946. For that same state and effective date this site derives 18.75, roughly ten times the filed figure.
Two notes on reading those numbers. Advisory loss costs exclude expense provisions, so a carrier's actual rate is the loss cost multiplied by a loss-cost multiplier greater than one; that widens the gap rather than explaining it, because our figures sit above the filed loss cost, not below. And the Georgia table we compared against is the edition effective 1 March 2025 — the 2026 filing cut Georgia loss costs a further 8.8%, so the real gap today is slightly wider than measured.
Until this is corrected, treat every per-$100 figure on this site as a relative indicator — useful for ranking one state or class code against another, which is what the comparison tables are for — and not as an estimate of what you will pay. For a figure you can rely on, use your state bureau's own published loss costs, linked below, or a quote from a licensed agent.
Where the numbers come from
The bodies that govern each jurisdiction, and that publish the filings a figure on this site should ultimately be reconciled against, are:
- National Council on Compensation Insurance (NCCI) — the rating organization in roughly two-thirds of states. Our guide to what NCCI is and how it sets loss costs explains the filing cycle these figures follow.
- Workers' Compensation Insurance Rating Bureau of California (WCIRB) — California sets its own pure premium rates independently of NCCI, on its own Standard Classification System rather than NCCI codes (WCIRB bureau profile)
- New York Compensation Insurance Rating Board (NYCIRB) (NYCIRB bureau profile)
- Independent state bureaus, including the Pennsylvania Compensation Rating Bureau (PCRB), Delaware (DCRB), New Jersey (NJCRIB), and North Carolina (NCRB). Each has its own profile here — PCRB, DCRB, NJCRIB, NCRB — setting out which classification system that state uses and why its loss costs are not interchangeable with NCCI's
- Monopolistic state funds — coverage is bought directly from the state, e.g. Ohio BWC, Washington L&I, North Dakota WSI, and Wyoming
Each state's rate page links to the specific bureau or filing it draws from. Independent-bureau states are never conflated with NCCI loss costs. Bureau links above were last verified 2026-07-09. The full directory of workers' comp rating bureaus by state covers the remaining independent bureaus, including Michigan (CAOM), Indiana (ICRB), Minnesota (MWCIA), Wisconsin (WCRB) and Massachusetts (WCRIBMA).
How often the data is refreshed
Most states refile loss costs or rates annually, on staggered effective dates (for example, Florida typically in December, California in January, New York in October). We re-verify state filing dates and bureau classifications on a rolling schedule and stamp each state and class-code page with a visible “last verified” date, and the page's modification date advances when it changes.
We want to be precise about what that re-verification does and does not cover, because the two are easy to conflate. It covers the things we cite: which bureau governs a state, the coverage threshold, and the effective date of the filing in force. It does not mean the per-$100 figures have been re-derived from that filing — as the calibration section above sets out, they have not been, and correcting that is the open work on this site rather than something already done.
Limitations — read before relying on a figure
- These are modeled benchmarks, not carrier quotes. Two insurers can file very different rates for the same class code in the same state.
- The state index is a relative scaling factor, not a guarantee that every class code moves by the same multiple in every state.
- Final premiums depend on your experience modifier, payroll audit, schedule rating, deductible, minimum premium, and statutory assessments — none of which a base-rate benchmark can capture.
- Class-code assignment is governed by the applicable scopes manual and should be confirmed with your carrier or a licensed agent.
For the full legal disclaimer, see our disclaimer page. This page is informational and is not insurance, legal, or financial advice.
Spotted something off?
We take data accuracy seriously. If a base rate, state index, effective date, or bureau classification looks wrong, check the source filing linked on the relevant state or class-code page — and let us know via the contact details on that page.