W-9 for LLC: How to Fill Out Form W-9 Based on Tax Classification
The most common W-9 mistake LLC owners make is checking the wrong tax classification box. How you fill out a W-9 depends entirely on whether your LLC is a single-member disregarded entity, a partnership, or a corporation. This guide explains every field — with clear examples for each LLC type.
How your LLC fills out a W-9 depends on its tax classification. Single-member LLC (disregarded entity): Owner's name on Line 1; LLC name on Line 2; check "Individual/sole proprietor or single-member LLC." Multi-member LLC (partnership): LLC name on Line 1; check "Partnership"; use LLC's EIN. LLC taxed as S-corp: LLC name on Line 1; check "S Corporation"; use LLC's EIN. The exact requirement depends on your LLC's IRS tax classification. This page is informational only and is not tax advice.
What Is Form W-9 and Why Do LLC Owners Fill It Out?
Form W-9 (officially the "Request for Taxpayer Identification Number and Certification") is the IRS form that U.S. businesses and contractors use to provide their tax ID number to a payer. When a client or customer hires your LLC and expects to issue a 1099-NEC or 1099-MISC at year-end, they will ask your LLC to complete a W-9 first.
The W-9 is not filed with the IRS. You give it to the requesting party — the client or vendor — so they have your correct information for their records and year-end tax reporting.
When Does an LLC Need to Fill Out a W-9?
Your LLC will typically receive a W-9 request when:
- A client expects to pay your LLC $600 or more in a calendar year for services
- A client is onboarding new vendors and requires tax documentation upfront
- You receive certain types of payments (rents, royalties, proceeds from broker transactions)
- A financial institution needs your tax information
You do not send a W-9 to the IRS. You give it directly to the requesting party.
Tax Classification Box (Line 3a): The Most Important Decision
Line 3a on Form W-9 is where you check your federal tax classification. This is where LLC owners most often make mistakes. Here is what to check based on how your LLC is taxed:
| LLC Tax Classification | Check This Box on Line 3a | Tax ID to Use (Part I) |
|---|---|---|
| Single-member LLC (disregarded entity) | "Individual/sole proprietor or single-member LLC" | Owner's SSN or LLC's EIN |
| Multi-member LLC (default partnership) | "Partnership" | LLC's EIN (required) |
| LLC with S-corp election | "S Corporation" | LLC's EIN (required) |
| LLC with C-corp election | "C Corporation" | LLC's EIN (required) |
Line 3a does not have a standalone "LLC" checkbox. The LLC box on Line 3a is for a specific situation: an LLC that is itself owned by another entity and has made a specific classification election. Most standard LLCs should not check this box. Select the classification that matches how your LLC is taxed (individual, partnership, S-corp, or C-corp).
Line 1 vs Line 2: The Single-Member LLC Confusion
Line 1 asks for the name "as shown on your income tax return." Line 2 asks for a business name or disregarded entity name (if different).
Here is how this maps to LLC types:
| LLC Type | Line 1 | Line 2 |
|---|---|---|
| Single-member LLC (disregarded entity) | Owner's personal legal name | LLC's name (e.g., "Jane Smith Consulting LLC") |
| Multi-member LLC (partnership) | LLC's legal name | Leave blank (or DBA if applicable) |
| LLC taxed as S-corp or C-corp | LLC's legal name | Leave blank (or DBA if applicable) |
The most common Line 1 mistake: a single-member LLC owner puts the LLC's name on Line 1 instead of their own personal name. For a disregarded entity, the IRS considers the owner as the taxpayer — so the owner's name goes on Line 1, and the LLC name goes on Line 2.
EIN vs SSN: Which Tax ID to Enter in Part I
Part I of Form W-9 asks for your Taxpayer Identification Number. You must enter either your Social Security Number (SSN) or your Employer Identification Number (EIN) — not both.
| LLC Type | Use SSN? | Use EIN? | Notes |
|---|---|---|---|
| Single-member LLC (disregarded) | ✓ Allowed | ✓ Allowed | EIN recommended for privacy |
| Multi-member LLC (partnership) | ✗ Not applicable | ✓ Required | Partnership must use EIN |
| LLC taxed as S-corp | ✗ Not applicable | ✓ Required | Corporate entity uses EIN |
| LLC taxed as C-corp | ✗ Not applicable | ✓ Required | Corporate entity uses EIN |
→ Full guide: W-9 for LLC: Should You Use an EIN or SSN?
W-9 Examples by LLC Type
Example 1: Single-Member LLC (Disregarded Entity)
Maria Johnson owns "Maria Johnson Design LLC," a single-member LLC. She has not elected S-corp or C-corp treatment. Her LLC is a disregarded entity.
- Line 1: Maria Johnson
- Line 2: Maria Johnson Design LLC
- Line 3a: Individual/sole proprietor or single-member LLC ✓
- Part I: Her EIN (preferred for privacy) or SSN
Example 2: Multi-Member LLC (Partnership)
Two partners, Marcus and Diego, formed "Blue Ridge Consulting LLC" together. No corporate election has been made — it is taxed as a partnership.
- Line 1: Blue Ridge Consulting LLC
- Line 2: (leave blank)
- Line 3a: Partnership ✓
- Part I: Blue Ridge Consulting LLC's EIN
Example 3: LLC Taxed as S-Corporation
Sarah Kim's "Kim Strategy Group LLC" has elected to be taxed as an S-corporation by filing Form 2553.
- Line 1: Kim Strategy Group LLC
- Line 2: (leave blank)
- Line 3a: S Corporation ✓
- Part I: Kim Strategy Group LLC's EIN
Common LLC W-9 Mistakes
- Putting LLC name on Line 1 (single-member): For disregarded entities, the owner's personal name belongs on Line 1. LLC name goes on Line 2.
- Checking the wrong tax classification box: "LLC" is not a standalone tax classification on the W-9. Choose Individual, Partnership, S-Corp, or C-Corp based on your actual tax treatment.
- Using SSN when EIN is required: Partnerships and corporate-taxed LLCs must use their EIN — not a member's SSN.
- Leaving Part I blank: The TIN is required. An unsigned or incomplete W-9 may trigger backup withholding.
- Forgetting to sign Part II: The certification signature in Part II is required. An unsigned W-9 is invalid.
- Sending by unsecured email: Your W-9 contains your SSN or EIN. Never send it via unencrypted email. Use a secure portal or encrypted file sharing.