If you have a physical Global Entry card, you can find your Known Traveler Number on the back. It's designated as a PASSID number, made up of nine digits. You can usually find your KTN on the TSA or Trusted Traveler Program (TTP) websites as well.

Excellent question! The numbers on the back of a Global Entry card are not random; they serve specific identification and security purposes.

Here’s a breakdown of what you’ll find on the back of the card:

1. The Most Important Number: The PASSID

This is the PASSID (PASSenger IDentification number). It’s a unique 9-digit identifier assigned to you by U.S. Customs and Border Protection (CBP). What it’s for: This is the number you use when booking flights internationally. Airlines transmit this number to CBP, which links it to your flight reservation and pre-clears you for expedited entry. It is not the same as your Known Traveler Number (KTN), but they are linked in CBP’s system. Format: Typically, it’s 9 digits, often printed near the top or middle of the back of the card.

2. The Machine Readable Zone (MRZ)

This is the two-line string of letters, numbers, and chevrons (<) at the very bottom of the card. It’s the same technology used in passports. What it’s for: It can be scanned by automated readers at Global Entry kiosks, NEXUS lanes (in Canada), and SENTRI lanes (at the U.S.-Mexico border). The MRZ encodes your name, PASSID, nationality, date of birth, and card expiration date. Format: Looks like this: ``` P<USASMITH<<JOHN<EDWARD<<<<<<<<<<<<<<<<<< 123456789<