Quick Answer: On Form W-9 (Rev. March 2024), a single-member LLC that has not elected corporate taxation checks the "Individual/sole proprietor" box on Line 3a — not the LLC box. Only an LLC taxed as a partnership or corporation checks the "Limited liability company" box and enters C, S, or P. The new Line 3b stays blank for almost everyone. Enter your name and TIN, sign Part II, and give the form to your client — never to the IRS.
If a US client, marketplace, or bank has asked your LLC for a W-9, they need it to report what they pay you — usually on a Form 1099 at year-end. The form looks trivial, but one wrong checkbox on Line 3a is the most common reason a W-9 gets bounced or triggers 24% backup withholding. This guide is written specifically for LLC owners and uses the current Rev. March 2024 form. If you would rather not fill it by hand, our free W-9 generator builds it in your browser — your SSN or EIN never leaves your device.
What a W-9 actually does for an LLC
A W-9 ("Request for Taxpayer Identification Number and Certification") gives your correct name, federal tax classification, and taxpayer ID to a business that pays you. That payer — your client, a platform like Upwork or Amazon, a bank paying interest — keeps the W-9 on file and uses it to issue you a 1099 and to report the payments to the IRS. You never send the W-9 to the IRS yourself. You hand it to the requester through a secure channel. When you bill that client, the free invoice generator produces a professional US invoice with your LLC details.
Why it matters: if you do not provide a valid W-9, or the name and TIN you give do not match IRS records, the payer is required to apply 24% backup withholding — they keep 24 cents of every dollar and send it to the IRS. Getting the form right the first time is the whole game.
Step 1: Know your LLC's federal tax classification
Everything on the form flows from one question: how is your LLC taxed? There are four possibilities:
- Single-member LLC (disregarded entity) — the default when one person owns the LLC. The IRS ignores the LLC for income tax and treats it like a sole proprietorship.
- Multi-member LLC (partnership) — the default with two or more owners. The LLC files Form 1065.
- LLC taxed as an S corporation — you filed Form 2553. (See our S-Corp election guide.)
- LLC taxed as a C corporation — you filed Form 8832.
If you have never filed Form 2553 or 8832, you are a disregarded entity (one owner) or a partnership (multiple owners) by default. Our LLC taxation guide walks through each path with worked numbers.
The box most LLCs check wrong (Line 3a)
Line 3a asks you to check one of seven federal tax classification boxes. Here is the trap: a single-member LLC does not check the "Limited liability company" box. A disregarded entity has to check the box for the tax classification of its owner. For most one-person LLCs, that is "Individual/sole proprietor."
| Your LLC is… | Check this Line 3a box | Enter code? |
|---|---|---|
| Single-member, no election (disregarded) | Individual/sole proprietor | — |
| Multi-member, no election (partnership) | Limited liability company | P |
| LLC taxed as S corp (Form 2553) | Limited liability company | S |
| LLC taxed as C corp (Form 8832) | Limited liability company | C |
Only check the "Limited liability company" box if your LLC is taxed as a partnership or corporation, and then you must write C, S, or P in the entry space. Checking "LLC" and leaving that code blank is the second most common error — it makes your form ambiguous and invites a rejection.
Line 1 vs Line 2: whose name goes where
This is where real-world rejections happen, because Line 1 and Line 3a have to agree:
- Disregarded single-member LLC: put the owner's legal name on Line 1 and the LLC's name on Line 2. The TIN must match the name on Line 1.
- Multi-member LLC or LLC with a corporate election: put the LLC's legal name on Line 1; Line 2 is optional.
If you put the LLC name on Line 1 for a disregarded entity and then enter the owner's SSN, the name and number will not match IRS records — and that mismatch is exactly what triggers backup withholding.
Line 3b: the March 2024 checkbox — and when to ignore it
The March 2024 revision added Line 3b. Most guides online were written for older versions and either skip it or explain it badly, so here is the plain-English rule.
You check Line 3b only if all of these are true: (1) on Line 3a you checked "Partnership" or "Trust/estate," or checked "LLC" with code "P"; (2) you are giving this W-9 to a partnership, trust, or estate in which you have an ownership interest; and (3) that flow-through entity has foreign partners, owners, or beneficiaries.
For the overwhelming majority of LLCs filling out a W-9 for a normal US client, Line 3b stays blank. A single-member LLC never checks it. If you are a non-resident owner, our non-resident LLC guide covers the related reporting in detail.
SSN or EIN? A decision rule for LLCs
Part I asks for one taxpayer identification number. Which one?
| Situation | Technically required | What we recommend |
|---|---|---|
| Disregarded SMLLC, US owner | Owner's SSN (or the LLC's EIN if the owner has one) | Use the LLC's EIN to keep your SSN private |
| Multi-member LLC / corporate election | The LLC's EIN | EIN |
| Non-resident-owned LLC | The LLC's EIN (owner has no SSN) | EIN — see how to get an EIN without an SSN |
The honest trade-off: a disregarded SMLLC's TIN is technically the owner's SSN, but the IRS also accepts the LLC's EIN, and handing your SSN to every payer is a privacy and fraud risk. If your LLC has an EIN, use it. If you do not have one yet, you can get one free from the IRS.
Lines 4–7: exemptions, address, account numbers
Line 4 (exemption codes) applies to certain entities, not individuals — most LLCs leave it blank. Lines 5 and 6 are your mailing address. Line 7 (account numbers) is optional. Do not overthink these.
Two worked examples
Example 1 — freelance designer, single-member LLC. Maria runs "Maria Design LLC," a one-owner LLC she never elected anything for. On her W-9: Line 1 = Maria [Last name] (her name), Line 2 = Maria Design LLC, Line 3a = Individual/sole proprietor, Line 3b blank, TIN = the LLC's EIN. She signs Part II and emails it to her client.
Example 2 — two-partner agency, multi-member LLC. "Northbound Media LLC" has two members and never made an election, so it is a partnership. On its W-9: Line 1 = Northbound Media LLC, Line 3a = Limited liability company with code P, Line 3b blank (no foreign partners, and it is going to a normal client), TIN = the LLC's EIN.
Skip the manual form: generate your W-9 in the browser
Our free W-9 generator walks you through Line 3a, handles the C/S/P code and Line 3b logic automatically, formats your SSN or EIN, and produces a clean W-9 (Rev. March 2024) you can print or save as PDF. Critically, it runs entirely in your browser — your taxpayer ID is never transmitted to or stored on any server. Fill it, download it, sign it, send it.
6 common W-9 mistakes LLCs make
- Checking the "LLC" box for a single-member disregarded LLC (should be "Individual/sole proprietor").
- Checking the "LLC" box but leaving the C/S/P code blank.
- Putting the LLC name on Line 1 for a disregarded entity, causing a name/TIN mismatch.
- Overthinking Line 3b and checking it when it does not apply.
- Using an old pre-March-2024 form (it lacks Line 3b).
- A name/TIN combination that does not match IRS records — which results in a CP2100 notice and 24% backup withholding.
Frequently asked questions
Can I refuse to fill out a W-9? You can, but the payer must then withhold 24% of your payments and send it to the IRS. For a legitimate client request, providing the W-9 is almost always in your interest.
Do I pay taxes on a W-9? No. A W-9 is informational. It does not create a tax — it lets the payer report payments to you. You pay tax on the income when you file your return.
Which TIN does a non-resident-owned LLC use? The LLC's EIN. A non-resident owner has no SSN; see our EIN-without-SSN guide.
Is this the current form? Yes — the current Form W-9 is Rev. March 2024, which introduced Line 3b. Always download the latest from the IRS before filing.
This article is educational and not tax advice. Verify against the official form at irs.gov/forms-pubs/about-form-w-9 and consult a tax professional for your situation.