Contractor workers comp class codes, and why they set your premium.
Your workers compensation premium starts with a class code. Get the code wrong, or assign payroll to the wrong one, and you either overpay or get a surprise at audit. This is a plain-language reference to the common construction codes and how they work. It is not a rate quote or legal advice.
Worried about a code or an audit? Get a quote or have us review your classification.
The common construction class codes
These are the NCCI codes most contractors see. Exact assignment depends on your operations and your state, and codes and rates are set by NCCI (or WCIRB in California), so treat this as a reference and confirm your assignment.
| Trade | Common NCCI code | Notes |
|---|---|---|
| Roofing | 5551 | Among the highest-rated construction codes, driven by fall exposure |
| Electrical (wiring within buildings) | 5190 | Lower hazard; watch for higher-rated line or outside work |
| Plumbing | 5183 | Plumbing NOC; separate from HVAC work |
| HVAC and refrigeration | 5537 | Installation and service; often split from plumbing payroll |
| Carpentry, detached one and two-family dwellings | 5645 | Higher rate; residential framing exposure |
| Carpentry NOC | 5403 | Commercial and other carpentry not otherwise classified |
| Painting | 5474 | Painting NOC and shop; height work raises the rate |
| Drywall and wallboard | 5445 | Installation within buildings |
| Concrete construction NOC | 5213 | Structural concrete; flatwork often 5215 |
| Masonry | 5022 | Brick, block, and stone |
| Tile, stone, and mosaic | 5348 | Interior finish work |
| Excavation and grading | 6217 | Earthmoving; scope can shift the code |
| Landscape gardening | 0042 | Planting and construction work; higher than lawn maintenance |
| Lawn care and maintenance | 9102 | Mowing and upkeep; a lower rate than 0042, and a common reclassification opportunity |
| Contractor executive supervisor | 5606 | Supervisors who do not perform manual labor; a much lower rate |
| Clerical office | 8810 | Office staff; one of the lowest rates |
Reference only. Codes and rates are set by NCCI, or by WCIRB in California, and change. Your correct classification depends on the work you actually perform. Confirm your assignment before relying on it. Not legal or coverage advice.
How a code becomes a premium
The math is simple and unforgiving. Each code carries a base rate per $100 of payroll. Multiply that rate by your payroll in the code, then apply your experience modifier, and that is the premium for that class. Because a high-hazard code like roofing can run several times a low-hazard code, moving payroll into or out of the right class changes the bill substantially. That is why the class code, not just the limit, is the number to get right.
Where misclassification costs you
Two failures show up at audit. The first is the wrong code entirely, work classified as something lower or higher risk than it is. The second is payroll allocated to the wrong code, often when supervisors or split-duty crews are lumped into the field code instead of their own. Both surface when the carrier trues up estimated payroll against actual, and the correction can be a bill you did not budget for.
Splitting payroll the right way
Contractors who do more than one kind of work can legitimately split payroll across codes, and can carry standard codes for clerical and outside sales. But the split has to be supported by real records, time and payroll by function. Done right, it lowers cost honestly. Done loosely, it invites an audit adjustment. Good records are the whole game.
California is different
California does not use NCCI codes. It runs its own classification system through the Workers Compensation Insurance Rating Bureau (WCIRB), so a California contractor's code will not match the NCCI number even for the same trade. If you work across state lines, expect different codes and rates on each side, and classify to each state's system.
Reviewed for insurance accuracy by Richard Sweet, Vantage Point Risk. Last reviewed July 16, 2026. How we review this.
Common questions.
What is a workers comp class code?
Why does my class code matter so much?
Can one contractor have several class codes?
How do I know my code is right?
Have us check your classification before the audit does
A wrong code or a bad payroll split is a bill waiting to happen. We review the classification against what your crews actually do.
Get the class codes right, and the audit gets easy.
Tell us your trades and how your crews split their time and we will review the classification and prepare you for audit.