What Form W-9 means
This is the IRS form a contractor or vendor fills out to give you their taxpayer identification number, so you can report what you paid them.
Also called W-9.
Where it shows up in your business
Get a W-9 before the first payment to any sub; chasing it in January is much harder. Keep it on file with the vendor's insurance certificate.
The numbers, with sources
- The IRS calls this form the Request for Taxpayer Identification Number (TIN) and Certification. (IRS)
Work it out
- Money guide: W-9 and 1099-NEC deadlines
- Money: Money guides for contractors
Sources: IRS, About Form W-9. Checked October 9, 2026.