What is the difference between I-20 and F-1 visa?

I-20 (Certificate of Eligibility):

• Document issued by school (DSO)
• Shows you're eligible for F-1 status
• Required for F-1 visa application
• Must be valid and current to maintain F-1 status
• Can have multiple I-20s (if transferring schools)

F-1 Visa Stamp:

• Sticker in passport from U.S. consulate
• Allows you to enter U.S.
• Can expire while F-1 status remains valid
• Need valid visa to re-enter after travel