Workers’ compensation class codes are three- or four-digit numbers that insurers attach to each type of work your employees perform, and the code assigned to a job sets the rate you pay per $100 of payroll for that worker’s coverage. Because the rates attached to different codes vary wildly, the code is the single biggest factor in what a workers’ comp policy costs. A roofing crew and a room full of data-entry clerks with identical total payroll land in completely different pricing tiers.
How a Class Code Sets Your Premium
The base calculation is simple. Take the payroll for each classification, divide by 100, and multiply by the rate assigned to that code. Then apply your experience modification factor. That’s your premium.
The size of what the code does becomes obvious with numbers. A business with $500,000 in annual payroll under a code carrying a rate of $2.50 per $100 owes a base premium of $12,500. A clerical operation with the same $500,000 payroll at $0.15 per $100 owes $750. A roofing contractor with that payroll at a rate above $13.00 per $100 faces a base premium north of $65,000. Same payroll, three very different bills, driven entirely by the code.
One detail trips up new employers: the “payroll” figure in the formula is actually “remuneration,” which is broader than wages. It typically includes bonuses, commissions, overtime, vacation and holiday pay, and even the value of housing or a car allowance. Leaving those out of your application lowballs the estimated premium, and the gap shows up at audit.
Governing Classification and the Three Standard Exceptions
Most of your payroll usually sits under a single “governing classification” — the basic code that fits the main work of the business and carries the largest share of payroll on the policy.1National Council on Compensation Insurance, Inc. (NCCI). Heterogeneity of Office and Clerical Classifications A plumbing company’s governing code covers its plumbers. A restaurant’s covers its cooks and servers.
Three roles show up across almost every industry, and NCCI pulls them out as “standard exception” classifications rather than lumping them in with the governing code:
- Code 8810, Clerical Office Employees, covers workers whose duties stay limited to record-keeping, correspondence, data entry, phone work, and similar desk tasks. It carries one of the lowest rates in the system.1National Council on Compensation Insurance, Inc. (NCCI). Heterogeneity of Office and Clerical Classifications
- Code 8742, Outside Salespersons or Collectors, covers employees who spend their time visiting clients or collecting payments away from the employer’s premises.2National Council on Compensation Insurance, Inc. (NCCI). NCCIs Classification Research – Top Reclassified Codes in 2024
- Code 7380, Drivers and Chauffeurs, covers commercial drivers, messengers, and their helpers.2National Council on Compensation Insurance, Inc. (NCCI). NCCIs Classification Research – Top Reclassified Codes in 2024
Each exception gets its own rate on the policy. The practical result: a roofing company’s office manager who never sets foot on a job site goes under Code 8810, not the high-rate roofing code. Splitting payroll correctly across the governing code and the exceptions is often the easiest premium reduction available to a small business.
How Codes Get Assigned
An underwriter chooses the codes at the start of the policy by looking at what the business actually does and where employees spend their time. They don’t go by your company name or by job titles on an org chart. The code follows the task, not the title.
An employee called “assistant manager” who spends most of a shift operating a forklift in a warehouse belongs under the warehouse code, not clerical. Detailed, accurate job descriptions are the single best tool an employer has for getting the initial classification right. The governing classification itself is the basic classification (excluding standard exceptions) that produces the greatest amount of payroll; if no basic classification applies, the standard exception with the most payroll becomes the governing code.1National Council on Compensation Insurance, Inc. (NCCI). Heterogeneity of Office and Clerical Classifications
Your Experience Modification Rate
Once you’ve been in business long enough to accumulate claims history, the class rate stops being the whole story. NCCI and state rating bureaus calculate an experience modification rate — the “e-mod” or “mod” — that compares your actual losses to the average for employers in the same classification.3National Council on Compensation Insurance. ABCs of Experience Rating
A mod of 1.00 means your losses are exactly average. A credit mod below 1.00 lowers your premium; a debit mod above 1.00 raises it. The math is simple multiplication. A $100,000 base premium at a 0.75 mod becomes $75,000. The same base premium at a 1.25 mod becomes $125,000.3National Council on Compensation Insurance. ABCs of Experience Rating
This is where workplace safety pays for itself. Training, proper equipment, and a return-to-work program after injuries keep claims down and push the mod lower over time. A bad year with multiple serious injuries can inflate the mod for several rating periods, so the pain compounds.
Audits and the Cost of a Wrong Code
Every policy is priced up front on estimated payroll, then reconciled against actual numbers after the policy period ends. A premium auditor reviews payroll registers, tax filings, job descriptions, and sometimes certificates of insurance for subcontractors to confirm that the classifications match what really happened.
If actual payroll came in higher than estimated, or an employee was assigned to a lower-risk code than their duties warrant, you get a bill for the difference. If you overpaid, you get a credit. These adjustments are normal.
Audits turn painful when the classification itself was wrong from the start. An employer who listed warehouse workers under a clerical code faces a retroactive recalculation at the correct, higher rate across the whole policy period. On a large payroll that back-billing can be substantial.
Honest mistakes lead to audit adjustments. Intentional misclassification — deliberately understating risk to pay less — is insurance fraud. Penalties vary by state but can include civil fines per misclassified employee, criminal charges carrying potential prison time, and court-ordered restitution for the underpaid premiums plus interest. Some states publish the names of convicted employers on their department of insurance website, and a fraud conviction can make private coverage hard to obtain at all, pushing the employer into the state’s assigned-risk pool at higher rates.
Even unintentional misclassification causes downstream problems. If a worker is injured and the policy has the wrong code, the claim still gets paid (workers’ comp is a no-fault system), but the carrier adjusts the premium retroactively and may non-renew the policy afterward.
How to Look Up or Dispute a Code
NCCI maintains an online Class Look-Up tool that lets employers, agents, and carriers search for classification codes by description, code number, or state. It provides code phraseologies, effective dates, and links to the Scopes descriptions explaining what operations and job duties each code covers.4NCCI. Class Look-Up The full Scopes Manual is part of NCCI’s Atlas Underwriting Bundle, which affiliates can access for free and non-affiliates can license for $250 per year.5NCCI. Scopes Manual (part of Atlas Underwriting Bundle)
If you believe your classification is wrong, start by raising it with your carrier. Most disagreements get resolved there. When they don’t, NCCI runs a formal Dispute Resolution Process for policyholders in states where NCCI manual rules apply. It covers disputes about classifications, experience rating, and other rules used to calculate premiums, and it’s designed to resolve issues without litigation.6NCCI. Dispute Resolution Process In states with their own rating bureaus, the bureau runs its own procedures.
Which System Applies in Your State
NCCI is the primary rating and statistical organization for workers’ compensation in the majority of U.S. states. It collects loss data from insurers nationwide, maintains the classification code system, and files recommended rates with state insurance departments.7NCCI. About Us
Several states run their own independent rating bureaus instead: California, Delaware, Indiana, Massachusetts, Michigan, Minnesota, New Jersey, New York, North Carolina, Pennsylvania, and Wisconsin. Their codes may differ from NCCI codes, so an employer expanding into one of these states needs to verify the local classification rather than assume an existing NCCI code transfers.
Four states — Ohio, North Dakota, Washington, and Wyoming — operate monopolistic state funds. Employers there cannot buy workers’ comp from a private insurer. Coverage must be purchased through the state-run fund, which sets its own rates and classifications. Understanding your class code still matters in those states; you simply deal with the state fund rather than shopping among private carriers.