Where to Fax Form SS-8 (IRS Worker Status Determination)

Form SS-8, "Determination of Worker Status for Purposes of Federal Employment Taxes and Income Tax Withholding," asks the IRS to formally decide whether a worker is an employee or an independent contractor. That classification drives a great deal: whether the business must withhold income tax and pay its share of Social Security and Medicare (FICA) taxes, whether the worker gets a W-2 or a 1099, and whether the worker is eligible for certain benefits and protections. When there is genuine uncertainty or disagreement about the classification, either party can ask the IRS to make the call by filing Form SS-8.

Two very different filers use the form. A worker files Form SS-8 when they believe they have been misclassified as an independent contractor and treated as such (for example, paid on a 1099 with no taxes withheld) but think they are really an employee. A firm files Form SS-8 to get certainty about how to treat a worker or a whole class of workers going forward. The form asks detailed questions about the working relationship, and the IRS generally shares the filing with the other party to get their side before deciding.

The stakes behind Form SS-8 are significant. If a worker is an employee, the employer must withhold federal income tax, withhold and pay Social Security and Medicare taxes, and typically pay federal unemployment tax — and the worker receives a W-2. If the worker is truly an independent contractor, the business does not withhold, and the worker handles their own self-employment tax and receives a 1099-NEC. Misclassification can leave a worker paying the full self-employment tax on income that should have had the employer share paid, and can expose a business to back taxes and penalties.

A worker who believes they were misclassified often files Form SS-8 alongside Form 8919, "Uncollected Social Security and Medicare Tax on Wages," which lets them pay only the employee’s share of FICA rather than the full self-employment amount. The SS-8 determination provides the IRS’s formal position on the relationship, which supports that treatment.

The IRS does not use a single checkbox to classify workers; it weighs the whole relationship under common-law rules that fall into three broad categories. Behavioral control looks at whether the business directs and controls how the work is done — instructions, training, and the degree of oversight. Financial control looks at the business side of the arrangement — how the worker is paid, whether they can incur a profit or loss, whether they have unreimbursed expenses, and whether they offer their services to the market. The type of relationship looks at written contracts, whether benefits are provided, the permanency of the arrangement, and whether the services are a key aspect of the business.

No single factor is decisive; the IRS considers the entire picture. That is why Form SS-8 asks such detailed questions and invites you to attach supporting documents — contracts, pay records, job descriptions, and correspondence. The more complete and accurate your answers and attachments, the better the IRS can make an informed determination.

Complete and sign Form SS-8 for the tax period(s) at issue, attach the supporting documentation, and submit it to the single national determinations unit. You can fax it to 855-242-4481 or mail it to Internal Revenue Service, Form SS-8 Determinations, P.O. Box 630, Stop 631, Holtsville, NY 11742-0630. There is no fee, and the form must not be submitted with your tax return — it is a standalone request. The IRS only issues determinations for tax years for which the statute of limitations has not expired.

After you file, the IRS acknowledges the request and generally contacts the other party (the worker or the firm) for their perspective, since a fair determination needs both sides. The review can take six months or more. When the IRS reaches a conclusion, it issues a determination or an information letter explaining the worker’s status. Note that filing Form SS-8 does not extend the deadlines for filing a tax return or a claim for refund — a worker must still file any protective refund claim within the normal 3-years-from-filing or 2-years-from-payment window.