Guide
W-9 vs W-8: Which Form Does Your Vendor Need?
By Keelstar Team · Updated June 1, 2026
The short answer
U.S. persons and U.S. businesses complete a W-9. Foreign persons and foreign entities complete a W-8 (most commonly a W-8BEN or W-8BEN-E). If you're unsure of a vendor's status, ask before you pay — the form determines your reporting and withholding obligations.
The short answer
Domestic vendor → W-9. Foreign vendor → W-8. The W-8 family has several variants depending on whether the payee is an individual or entity and whether they're claiming treaty benefits.
Why it matters
Collecting the wrong form can lead to incorrect reporting and withholding. The form establishes the payee's tax status, which drives whether you issue a 1099 and whether backup or treaty withholding applies.
What to do when unsure
Don't guess. Ask the vendor to confirm their status, and route them to the correct form before the first payment.
Put this into a monitored workflow
W-9 Collector handles this continuously — with reminders and an audit trail.