W-9 for LLC: Should You Use an EIN or SSN?
Multi-member LLCs and LLCs taxed as corporations must use their EIN on Form W-9. A single-member LLC that is a disregarded entity has a choice: it can use the owner's SSN or the LLC's EIN. The EIN is almost always the better choice for privacy and professional appearance.
Multi-member LLCs (partnerships) and corporate LLCs must use their EIN. Single-member LLCs (disregarded entities) may use either the owner's SSN or the LLC's EIN in Part I of Form W-9. Using the EIN is strongly recommended — it keeps your Social Security Number off client records and reduces identity theft risk. Verify the correct TIN box placement using the IRS W-9 instructions for disregarded entities.
EIN vs SSN on W-9: Quick Reference
| LLC Type | Can Use SSN? | Can Use EIN? | Recommended |
|---|---|---|---|
| Single-member LLC (disregarded entity) | ✓ Yes | ✓ Yes | EIN (privacy) |
| Multi-member LLC (partnership) | ✗ No | ✓ Required | EIN (required) |
| LLC taxed as S-corp | ✗ No | ✓ Required | EIN (required) |
| LLC taxed as C-corp | ✗ No | ✓ Required | EIN (required) |
Why Use an EIN Instead of SSN on Your W-9?
For single-member LLCs that can use either, here is why EIN is almost always the better choice:
Privacy Protection
When you provide your SSN on a W-9, every client who receives that form now has your personal Social Security Number. If any of those clients experience a data breach, your SSN is exposed. A compromised SSN can be used for identity theft, fraudulent tax filings, and unauthorized credit applications. An EIN, if exposed, creates far less personal harm.
Professional Appearance
Providing an EIN on a W-9 signals that your LLC is a properly registered business with its own federal tax identity. Clients who frequently work with contractors appreciate receiving an EIN rather than an SSN on vendor forms.
Separation of Business and Personal Identity
Using your LLC's EIN reinforces the separation between your personal and business identities — which is a core principle of LLC protection. Mixing personal identifiers (SSN) into business transactions weakens this separation psychologically and practically.
No Cost
Getting an EIN is free. Once you have one, there is no reason not to use it on your W-9.
Where Does the EIN Go on a W-9?
Part I of Form W-9 has two boxes: one for Social Security Number and one for Employer Identification Number. You fill in only one.
For a single-member LLC using its EIN:
- Leave the "Social Security number" box blank
- Enter the LLC's 9-digit EIN in the "Employer identification number" box, formatted as XX-XXXXXXX
The IRS W-9 instructions note that for a disregarded entity providing an EIN: "If you are a single-member LLC that is disregarded as an entity separate from its owner, enter the owner's SSN (or EIN, if the owner has one). Do not enter the disregarded entity's EIN." This instruction can be confusing — the key point is that if you are entering an EIN for a disregarded single-member LLC, use the LLC's EIN (which is the "owner's EIN" in this context if the LLC has obtained one). Verify the current IRS W-9 instructions for any changes.
Getting an EIN for Your Single-Member LLC
If you do not yet have an EIN and want to use one on your W-9:
- Go to IRS.gov EIN Online Application
- Select "Limited Liability Company (LLC)" and "1 member"
- Complete the application with your SSN or ITIN
- Download your EIN Confirmation Letter (CP 575)
- Update your W-9 template with the new EIN
→ Full guide: EIN for Single-Member LLC
→ How to apply: How to Apply for an EIN for an LLC