What Is a W-9?
Form W-9 is the document a US freelancer gives each client before payment, supplying the taxpayer ID the client needs to file the freelancer's 1099-NEC.
How w-9 works
Form W-9 collects three pieces of information a client needs before paying you: your legal name, your business structure, and your taxpayer identification number (your SSN or EIN). You complete it once per client at the start of the relationship, sign it, and send it back; the client keeps it on file and never submits it to the IRS. The client uses your W-9 data to issue a 1099-NEC the following January whenever they pay you $600 or more in a calendar year. If you refuse to provide a W-9, the client must apply backup withholding and send 24% of every payment straight to the IRS, so a $5,000 invoice nets you only $3,800. Independent contractors, sole proprietors, single-member LLCs, and S-corps all file W-9s; W-2 employees never do, because that distinction marks the line between freelancing and employment. The pricing implication is direct: a W-9 signals that you are a self-employed business, not a payrolled worker, so no taxes get withheld from your invoices. You receive the full amount and owe 15.3% self-employment tax plus income tax yourself through quarterly estimated payments. Price accordingly. A rate that looks identical to a salaried hourly wage actually pays far less after you cover the employer-side taxes a client would otherwise have paid. Treat W-9 submission as routine paperwork, return it within a day, and build the tax load into your floor rate rather than discovering it at filing time.
Example
Why backup withholding costs you $1,200
A copywriter lands a $5,000 project with a new agency. The agency's accounts-payable team requests a W-9 before cutting the first check. If the copywriter returns it promptly, she invoices $5,000 and receives the full $5,000, then sets aside roughly $765 for the 15.3% self-employment tax and her income-tax share via quarterly estimates. If she ignores the request, the agency is legally required to apply 24% backup withholding: it pays the IRS $1,200 and sends her only $3,800. She still owes the same self-employment tax, and she must wait until she files her annual return to reclaim the over-withheld amount. Returning the one-page form the same day keeps $1,200 of cash flow in her account instead of the government's.
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