What Is a W-9 Form and Why Do You Need One?
The IRS Form W-9 (Request for Taxpayer Identification Number and Certification) is one of the most commonly requested documents in the United States. Businesses use it to collect your Tax Identification Number (TIN) so they can report payments made to you to the IRS. If you're a freelancer, independent contractor, or vendor, you'll likely encounter a W-9 request multiple times a year.
Who Needs to Fill Out a W-9?
- Freelancers and independent contractors receiving $600 or more from a single client in a tax year
- Sole proprietors providing services to businesses
- LLCs and partnerships receiving reportable payments
- Anyone receiving interest, dividends, or other income that must be reported to the IRS
Step-by-Step: Completing Each Line
Line 1 – Name
Enter your full legal name exactly as it appears on your tax return. If you're an individual or sole proprietor, this is your personal name, not a business name.
Line 2 – Business Name (Optional)
If you operate under a DBA (doing business as) or a disregarded entity name different from Line 1, enter it here. Leave blank if it's the same as Line 1.
Line 3 – Federal Tax Classification
Check the box that applies to you:
- Individual/Sole proprietor or single-member LLC — most freelancers check this
- C Corporation, S Corporation, or Partnership — for business entities
- Trust/estate — if applicable
- LLC — check this and enter the appropriate tax classification (C, S, or P)
Line 4 – Exemptions
Most individuals leave this blank. It applies to entities like corporations that are exempt from backup withholding. If you're unsure, leave it empty — entering incorrect codes can cause problems.
Lines 5 & 6 – Address
Enter your mailing address. This is where the requester will send any required notices or 1099 forms. Use the address associated with your tax return.
Line 7 – Account Numbers (Optional)
The requester may ask you to list account numbers here. This is optional and applies primarily to financial institutions.
Part I – Taxpayer Identification Number (TIN)
This is the most critical part of the form. Enter either your:
- Social Security Number (SSN) — for individuals and sole proprietors
- Employer Identification Number (EIN) — for businesses, LLCs, partnerships
Only enter one type of TIN. Do not enter both.
Part II – Certification
Sign and date the form. By signing, you certify that your TIN is correct and that you are not subject to backup withholding (unless you've been notified otherwise by the IRS).
Important Tips Before You Submit
- Never send a W-9 by email unless it is encrypted — it contains sensitive personal information.
- Double-check your TIN. A mismatch can trigger IRS backup withholding at a flat rate on your payments.
- Update your W-9 if your information changes (new address, new TIN, change in entity type).
- Keep a copy for your own records.
The W-9 itself is not filed with the IRS — only the requester keeps it on file. Still, accuracy matters because any errors flow directly into 1099 forms filed by the payer, which can create tax complications for you down the line.