How Does a Sole Proprietor Fill Out a W-9?
Which box to check on Line 3, whose name and TIN to use, for 2026.
By the Easy Guides Editorial Team
On a W-9 for a Sole Proprietor, the key is Line 3a: check the Individual/sole proprietor or single-member LLC box. Put your own name on Line 1 (your business/DBA name goes on Line 2 if you have one), and use your SSN, or an EIN if you have one as the taxpayer ID. Get those right and the rest of the form is straightforward.
Which box to check
As a sole proprietor you and your business are the same taxpayer. On Line 3a, check the very first box: “Individual/sole proprietor or single-member LLC.”
Whose name goes on Line 1
Line 1 must show your own name on Line 1 (your business/DBA name goes on Line 2 if you have one). Line 1 is never left blank and never holds a trade name by itself, the IRS matches it against the taxpayer ID, so a mismatch triggers backup withholding.
Which taxpayer ID to use
Use your SSN, or an EIN if you have one. If you need one, an EIN is free from the IRS. See SSN vs EIN on a W-9 for which to use.
Everything else is the same
The remaining lines, address, and signing in Part II, work the same for every entity. Our line-by-line W-9 walkthrough covers them.
Common questions
What box do I check on a W-9 for a Sole Proprietor?
Check the Individual/sole proprietor or single-member LLC box on Line 3a of the W-9. That single choice tells the payer how your business is taxed and which 1099 (if any) you'll receive.
Whose name goes on the W-9 for a Sole Proprietor?
Line 1 shows your own name on Line 1 (your business/DBA name goes on Line 2 if you have one). It has to match the taxpayer ID number you enter, or the payer must apply 24% backup withholding.
Do I use an SSN or EIN for a Sole Proprietor?
Use your SSN, or an EIN if you have one. Businesses generally should use an EIN, it's free from the IRS and keeps personal SSNs off the form.