What Determines the Cost of Contractor Insurance?
Short answer
Price is set per risk by a carrier, against rates filed for that state and that class of work, so no published figure describes a specific contractor's cost. What is stable is the list of inputs. Trade classification, the measure of how much work is done, the limits and deductibles requested, prior claims experience, and how subcontractors are handled appear on nearly every application. This page names the inputs. It does not publish prices, because a price that did not come from a carrier looking at your operation would be invented.
Why one number cannot be published
Rates are filed with state insurance departments and vary by state, by classification, and by carrier. Two contractors in the same trade, in the same city, with the same revenue, can be priced differently on the basis of claims history, subcontracting practice, and how the work is described. Any article that answers the cost question with a single figure has silently assumed a state, a class, a limit, a deductible, and a loss record. The honest answer is the list below plus a conversation with a licensed agent.
Classification
The first thing an application establishes is what the work actually is. Roofing, excavation, electrical, painting, and general carpentry are separate classes of risk, and a business that does several is usually described by the mix. Classification drives more of the outcome than most other inputs, which is why applications press for detail about the percentage of work by type, the height worked at, and whether any of the operations fall into categories a carrier declines.
The exposure basis
Coverage is priced against something that scales with the amount of work done. Depending on the line, that measure may be payroll, receipts, unit counts, or another basis, and the basis that applies is defined in the policy itself rather than by a general rule. Because the measure is an estimate at the start of the term, many commercial policies are subject to an audit afterward that reconciles the estimate against what actually happened. That reconciliation is a normal part of how the price is arrived at, not a penalty.
Limits, deductibles, and endorsements
The limits and deductibles requested are inputs to the price, and so are the endorsements a contract requires — additional insured status, waiver of subrogation, primary and non-contributory wording. Contracts frequently specify limits, so this input often arrives already decided. How limits and deductibles interact on a specific quote is a carrier and policy-form question; there is no general ratio worth repeating here.
Loss history
Carriers ask for loss runs, the record of claims paid and reserved under prior policies, supplied by previous carriers. The number of years requested is set by the carrier and the line. What the loss runs show — frequency more than any single severe claim — is a standard underwriting input. A contractor changing carriers is normally the party who requests loss runs from the expiring carrier.
Subcontractors
How a contractor uses subcontractors changes the picture substantially. Applications ask whether subcontractors are used, for what portion of the work, and whether certificates of insurance are collected from them. Uninsured subcontracted work tends to be treated as the contractor's own exposure. Collecting and tracking certificates is therefore both a contract-compliance task and an underwriting one. See how to read a certificate of insurance.
The security questions on a cyber application
Contractors adding cyber liability meet a different kind of questionnaire, focused on account controls rather than job sites. Applications commonly ask about multifactor authentication, password practices, backups, and patching, and they use terms that have precise public definitions.
The federal standard for those terms is NIST SP 800-63B-4, Digital Identity Guidelines: Authentication and Authenticator Management, finalized in July 2025, which sets requirements for password length, screening passwords against breach lists, hashing, and the authentication assurance levels multifactor requirements are expressed in. CISA's Secure Our World guidance covers the same four habits in non-technical language. The underlying loss types those controls address — account takeover, payment redirection — are among the crime categories the FBI's Internet Crime Complaint Center reports on publicly.
Where to look next
None of the references below set insurance prices; they are cited only for the security definitions in the section above. Rates and forms are filed with state insurance departments, and the authority on your own price is the carrier or licensed agent quoting it.