How to Fill Out a W-9 as a Contractor: Line by Line

To fill out a W-9 as a contractor, put your legal name on Line 1, your business or trade name on Line 2 if it differs, check the single box on Line 3 that matches your federal tax classification, enter the address where you want tax documents mailed, provide the taxpayer identification number that matches the name on Line 1, and sign Part II. The form goes back to the client who asked for it, not to the IRS.

The whole thing is one page. Five minutes if you know what belongs on each line. The rest of this walks through the form field by field, flags the mistake that most often triggers backup withholding, and covers what to do when your information changes.

First, Confirm It’s a W-9 and Not a W-4

A client who sends you a W-9 is treating you as an independent contractor. Employees fill out a W-4 instead, which tells an employer how much federal income tax to withhold from each paycheck. A W-9 collects your taxpayer ID so the client can file a 1099-NEC at year-end reporting what they paid you; nothing is withheld from your checks.¹

If you think you’re actually being treated as an employee (set hours, company equipment, direction on how to do the work), you can file Form SS-8 with the IRS to request a formal worker-status determination before signing anything.²

Lines 1 and 2: Your Name and Business Name

Line 1 is your legal name exactly as it appears on your tax return. If you’re a sole proprietor or single-member LLC, that’s your personal name, not your business name. For a corporation, partnership, or trust, use the entity name registered with the IRS.³

Line 2 is for a business name, trade name, or DBA that differs from Line 1. If you freelance as “Jane Smith Design” but your legal name is Jane Smith, Jane Smith goes on Line 1 and the business name on Line 2. Same name? Leave Line 2 blank.³

Line 3: Federal Tax Classification

Check one box. This is the line contractors get wrong most often, especially LLC owners.

Individual/sole proprietor: freelancing or running a business under your own name with no formal entity. Use your SSN as the taxpayer ID.
Single-member LLC treated as a disregarded entity: check the “Individual/sole proprietor or single-member LLC” box. Put your personal name on Line 1 and the LLC’s name on Line 2. Use either your SSN or the LLC’s EIN, but the name on Line 1 must match the name the IRS associates with that number.⁴
Multi-member LLC taxed as a partnership: check the “Limited liability company” box and write “P” in the space provided.⁵
LLC that elected S-corp or C-corp status: check the “Limited liability company” box and write “S” or “C” to match your election.⁵
C corporation or S corporation: check the corresponding box. Corporations are generally exempt from backup withholding on most payment types.
Partnership, trust, or estate: each has its own checkbox.³

The classic single-member LLC error: putting the LLC’s name on Line 1 and the LLC’s EIN in Part I, when the IRS actually has the owner’s SSN on file for that name. The mismatch generates a notice to the client and can trigger backup withholding on your future payments.⁴

Line 4: Exemption Codes

Most individual contractors leave Line 4 blank. The first code space is for backup withholding exemptions (numbered 1 through 13, for entities like tax-exempt organizations, government agencies, and corporations). The second is for FATCA reporting exemptions (lettered A through M). Neither applies to a typical freelancer.⁵

Lines 5 Through 7: Address and Account Number

Lines 5 and 6 take your street address, city, state, and ZIP code. Your client mails tax documents like the 1099-NEC to this address, so use one where you actually receive mail.³

Line 7 is optional. Some clients ask you to list an internal account or vendor number so they can match your W-9 to a specific project. If your client hasn’t mentioned one, skip it.³

Part I: Your Taxpayer Identification Number

Enter a nine-digit SSN or EIN. The number must correspond to the name on Line 1. Sole proprietor using your personal name on Line 1? Use your SSN. Business entity with the entity name on Line 1? Use the EIN assigned to that entity.³

This is the single most consequential field on the form. If the IRS can’t match your TIN to the name on Line 1, it notifies your client, and your client may be required to withhold 24% of every payment until the mismatch is resolved.⁶

Using an EIN to Keep Your SSN Off the Form

If you freelance for many clients, handing out your SSN every time creates real identity theft exposure. Even sole proprietors with no employees can apply for an EIN from the IRS. It’s free, takes minutes online, and lets you put an EIN in Part I instead of your Social Security number.⁴

If you do use your SSN, deliver the form through a client’s secure portal or an encrypted email rather than a plain attachment. Push back on any request to text a photo of the completed form.

Part II: Certification and Signature

You sign under penalties of perjury that four things are true: the TIN you provided is correct, you’re not subject to backup withholding (unless you’ve been notified otherwise), you’re a U.S. person, and any FATCA code you entered is correct. Read the certification language before signing. If the IRS has already notified you that you’re subject to backup withholding for underreporting interest or dividends, cross out item 2 of the certification before you sign.³

Green-card holders and other resident aliens who qualify as U.S. persons for tax purposes use the W-9 the same way U.S. citizens do.⁷

Returning the Form

Send the completed W-9 directly to the client who requested it. It does not go to the IRS. Your client keeps it on file and uses it to prepare year-end tax reporting.³

Clients can accept the form electronically, including by fax. Any electronic submission system they use must capture your electronic signature under penalties of perjury, using the same certification language as the paper form.⁸

When to Send a New W-9

A W-9 doesn’t expire on a set schedule. It stays valid until the information changes. Send an updated form to any client holding your old one when:

Your legal name or TIN changes, including switching from your SSN to a new EIN.³
Your entity restructures, for example a single-member LLC electing S-corp treatment, or a C-corp converting to an S-corp.
An exemption you previously claimed no longer applies.³
You move. The IRS won’t penalize you for a stale address, but your 1099-NEC will go to the wrong mailbox.

If you use an ITIN instead of an SSN, note that ITINs expire if they haven’t appeared on a federal tax return in the last three consecutive tax years. An expired ITIN has to be renewed before a client can process your W-9 without triggering a name-TIN mismatch.⁸

Backup Withholding and Penalties

Backup withholding is what happens when something goes wrong with your identification. If it kicks in, your client withholds 24% of every gross payment and sends it to the IRS on your behalf.⁹ It’s triggered when you fail to provide a TIN, when the IRS tells your client your TIN doesn’t match records, or when you’ve been flagged for underreporting interest and dividend income.⁶

To avoid it, make sure the name and TIN on your W-9 match the IRS’s records. Sole proprietors: your personal name with your SSN, not your trade name. Entities: the registered entity name with its EIN. If backup withholding has already started, you stop it by fixing the underlying issue and certifying on a new W-9 that you’re no longer subject to it.

Failing to furnish a correct TIN carries a $50 penalty for each failure, absent reasonable cause.³ Providing false information to dodge withholding adds a $500 civil penalty and potential criminal liability, since the certification is signed under penalties of perjury.¹⁰ Honest mistakes generally get resolved with a corrected form. The penalties that actually bite fall on contractors who ignore IRS notices or refuse to provide a TIN, because the 24% withholding starts automatically and doesn’t stop until the file is fixed.

1
Internal Revenue Service. About Form W-9, Request for Taxpayer Identification Number and Certification
2
Internal Revenue Service. Instructions for Form SS-8 (Rev. January 2024)
3
Internal Revenue Service. Form W-9 (Rev. March 2024) Request for Taxpayer Identification Number and Certification
4
Internal Revenue Service. Single Member Limited Liability Companies
5
Internal Revenue Service. Instructions for Form W-9 (Rev. March 2024)
6
Internal Revenue Service. Backup Withholding
7
Internal Revenue Service. Publication 519 (2025), U.S. Tax Guide for Aliens
8
Internal Revenue Service. Instructions for the Requester of Form W-9
9
Office of the Law Revision Counsel. 26 U.S. Code 3406 – Backup Withholding
10
eCFR. 26 CFR 31.6682-1 – False Information With Respect to Withholding