Independent contractor insurance, for a business with one person in it
Two questions sit under this search and they are not the same question. The first is what an independent contractor is, which is a classification test the IRS runs on control rather than on what your invoice says. The second is what a business with no employees and no premises actually buys, where the answer is general liability, the vehicle, the tools, and a workers compensation question whose real answer is that the policy covers employees and you do not have any. What the client asking you for coverage wants, and what your state requires, are two different lists, and this page keeps them apart.
Independent contractor general liability insurance: the first policy
A commercial general liability policy answers for four categories of event a business can be held responsible for, in the NAIC's list: bodily injury, damage to others' property, personal injury including slander and libel, and false or misleading advertising (NAIC, Insure U: Small Business Insurance). For a solo operator that list is shorter in practice than it looks. You have no premises, so the classic slip-and-fall on your own floor is not your exposure. What is left is what your work does to other people and their things at their address: the ladder that goes through a window, the client who trips on your cord, the wall you opened that was holding water.
The dividing line to get right early is what kind of work you sell. The NAIC lists professional liability, errors and omissions, among the risks a general liability policy does not answer for, and describes professional liability as covering wrongful practices by professional service providers. If what a client buys from you is judgment, a design, a plan, a specification, or advice, then the allegation that will arrive is that the judgment was wrong, and general liability is the wrong policy for it. If what a client buys is physical work, general liability is the spine and professional liability is the addition to consider. Plenty of one-person businesses sell both, and that is the case where the question needs asking out loud. The general liability coverage page takes the form apart in full.
Are you actually an independent contractor? The IRS common-law test
This matters before the insurance question, because if the answer is employee then the coverage question belongs to somebody else. The IRS states the general rule plainly: "An individual is an independent contractor if the person for whom the services are performed has the right to control or direct only the result of the work and not what will be done and how it will be done" (IRS, Independent contractor defined). Its worker-classification page sorts the evidence of control into three categories, each asked as a question: behavioral control, "Does the company control or have the right to control what the worker does and how the worker does his or her job?"; financial control, "Are the business aspects of the worker's job controlled by the payer? (these include things like how worker is paid, whether expenses are reimbursed, who provides tools/supplies, etc.)"; and type of relationship, "Are there written contracts or employee type benefits (that is, pension plan, insurance, vacation pay, etc.)? Will the relationship continue and is the work performed a key aspect of the business?" (IRS, Independent contractor (self-employed) or employee?).
The IRS is explicit that this does not resolve into a checklist: "The keys are to look at the entire relationship and consider the extent of the right to direct and control the worker," and "There is no 'magic' or set number of factors that 'makes' the worker an employee or an independent contractor and no one factor stands alone in making this determination." Where it stays unclear, either the business or the worker can file Form SS-8 and ask the IRS to determine status, though the IRS warns "it may take at least six months to receive a determination on your filing," and a business that treats an employee as a contractor without a reasonable basis "may be held liable for employment taxes for that worker." Being an independent contractor also means being self-employed, so "the earnings of a person who is working as an independent contractor are subject to self-employment tax."
One caution the tax articles usually skip. This is the federal tax test and only that. Your state's workers compensation agency and your state's labor department run their own tests, and they can classify the same working relationship differently. Notice, too, what the IRS's own financial-control question names as evidence: who pays for tools and supplies, and whether expenses are reimbursed. Carrying your own insurance, buying your own tools, and invoicing several customers are the facts that make the independent side of the argument, which is one reason coverage is worth having even in a year when no client demands it. The general contractor vs subcontractor guide works through the distinction on its own, including the subcontractor versus employee line inside a construction contract.
Independent contractor workers comp insurance, with no employees
Start with what the coverage is. Nearly all states require employers to purchase workers compensation to cover employees, requirements vary by state and business type, and the NAIC's advice is to check with the state (NAIC). Every operative word there is about employees. A one-person business has none. So in most states there is no employee for the policy to cover, and an injury to you personally is a health insurance and disability question rather than a workers compensation one. That is the part national content tends to blur, and it is worth being direct about: you are usually not breaking a law by not carrying it.
So why does the client keep asking? Because the requirement is theirs, not the state's. A company that hires you is managing its own exposure and its own insurance file, and it wants documentation covering the possibility that you get hurt on its site or that somebody later argues you were its employee. What it will accept is generally one of two things: a policy, or the exemption or waiver form its state defines for owners without employees. Which of those exists, what it is called, and who files it are all state questions, and the state's workers compensation agency is the place to settle them rather than a national article.
Texas is the state this network has read most closely and it sits outside the pattern in a useful way: the Texas Department of Insurance says private employers can choose to carry coverage and that it "is not required in most cases" (TDI, employer resources). Even there, a client's contract can require what the state does not, and declining coverage as an employer carries trade-offs that the Texas hub sets out. The day you hire your first helper the whole analysis changes in nearly every state, and the first thing to settle is whether that helper is an employee, which is the control test above, not the invoice.
The vehicle and the tools, which for a solo operator are the business
The vehicle. A business that owns or leases a vehicle needs commercial auto; personal auto policies may exclude business-related liability, and the NAIC tells owners relying on personal coverage for business use to look closely at the provisions (NAIC). The independent contractor's version of this problem is that the truck is one vehicle doing two jobs, and the question of which policy answers is decided after the accident by what you were doing at the time. Describe the actual use to an agent rather than hoping the personal policy stretches.
The tools. Business property coverage can include, owned or leased, equipment and supplies, machinery, inventory, and computers (NAIC). For a solo operator the tools are usually the single largest thing the business owns, and they live in a truck bed or a trailer overnight rather than at an address, which is a different kind of coverage question from property at a fixed location. Ask specifically how a theft from a locked truck at a hotel is treated. Operators working in a named trade should read the trade page too, since the equipment answer is different for a welder than for a handyman.
What a client will ask you to send
A certificate of insurance is "a document providing evidence that certain general types of insurance coverages and limits have been purchased by the party required to furnish the certificate," with the client named in the certificate holder box (IRMI, certificate of insurance). Evidence is all it is. ACORD, which publishes the standard forms, states that "A Certificate of Insurance is NOT an insurance policy, and does not serve to provide, endorse, amend, extend or alter in any way the terms of an insurance policy" (ACORD certificates FAQ, quoted in IRMI expert commentary, David Dybdahl, 2015, which quotes the ACORD page). If the client also wants to be an additional insured, that is a person or organization "included or added as an insured under the policy at the request of the named insured" (IRMI, additional insured), and it takes an endorsement rather than a typed line on the certificate.
If the client is a general contractor, the request will be longer than a certificate and each item on it has a price. That list, term by term, is on the subcontractor insurance page, and the reason the other side asks for it is on the general contractor insurance page.
What moves an independent contractor's premium
Inputs rather than a price, and here the spread is the point: this term covers a consultant with a laptop and a solo framer on a second story, so any single number would mislead most of the people reading it. What moves it: what the work physically involves and whether anybody can be injured by it; your annual receipts; the limits your clients require, which for commercial and public work are often higher than anything you would choose; whether you need professional liability alongside general liability, which depends on whether you sell judgment or labor; the vehicle and how much of its use is business; the tools you carry and where they sleep; your loss history; and your state. The lever you hold is description. An applicant described only as "independent contractor" is priced on the worst thing that phrase can mean, and one who describes the actual work, the actual sites, and the actual clients is priced on that instead.
Where to go next
If your clients are general contractors, the subcontractor page has the contract terms. If the question is really what the labels mean, start with the guide. If you work in a named trade, the trade page will be more specific than either.
Or start at the overview for how the whole contractor set fits together.