The Known Traveler ID number is located on the back of your Global Entry, NEXUS, or SENTRI card (for NEXUS, a PASSID printed on the front), and it also appears in your Trusted Traveler Programs account, in your TSA PreCheck notification email after approval, and on the receipt page shown at the end of the application. The same number is often called your PASSID.
That is the short answer for most travelers. The rest of this guide explains what the number actually is, why it lives in those specific places, how the printed formats differ by program, and where people most often copy the wrong digits.
What the number actually is
The Known Traveler Number is a unique identifier the Department of Homeland Security assigns when it approves you for a trusted traveler program. It is not your membership card's serial number, not your receipt number, and not your date of birth. It is the record key that ties your approved identity to your airline reservation.
Mechanically, the number works because airlines query the Secure Flight system before issuing a boarding pass. When you type the number into a booking, Secure Flight matches it against your approved traveler record. If the match succeeds, the airline prints the TSA PreCheck indicator on your boarding pass.
The identifier is program-specific in its formatting. Global Entry cards, NEXUS cards, and SENTRI cards each present the number differently, which is the single biggest source of confusion. The underlying record is the same, but the printed location changes by card design.
A useful plain-language anchor: think of the number as your membership ID at a gym, not the barcode on the key tag.
Where the digits physically sit, by format
On a Global Entry card, the Known Traveler Number is printed on the back, labeled as the PASSID. On a NEXUS card, the PASSID appears on the front. On a SENTRI card, it also appears on the card itself, and the layout follows the NEXUS convention. The exact label wording varies by card revision.
The card number and the Known Traveler Number are usually the same string for Global Entry and NEXUS, but the card's visible number is not always what you should enter. The program account is the authoritative source when the printed card is worn or ambiguous.
The number also appears in three non-card places that matter more for daily use. It shows in your TTP account dashboard, in the approval email, and on the final confirmation screen when you complete enrollment. If you lost the card, the account is the first place to look.
For TSA PreCheck enrollment through a private provider, the number is issued by that provider and appears in the provider's approval communication and in the TTP system once your record is created. The physical card situation differs from Global Entry, so rely on the account record.
Timeline: from application to usable number
| Stage | What happens | Where the number appears |
|---|---|---|
| Application submitted | Identity and background data captured | Not yet issued |
| Conditional approval | Interview scheduling opens | Account shows pending status |
| Interview completed | Officer finalizes the record | Number generated in the system |
| Approval notice | Decision communicated | Approval email and account dashboard |
| Card production | Physical card mailed | Number printed on card |
| First booking use | Airline queries Secure Flight | You enter the number manually |
| Renewal | Record extended after review | Number typically retained |
The key timing fact is that the number becomes usable at approval, not at card delivery. Travelers who wait for the plastic card before booking lose weeks of eligibility. Enter the number from your account as soon as the approval notice arrives.
Renewal is the second timing trap. Most programs retain the same identifier across renewals, but a lapse in status can suspend eligibility even though the number is unchanged. The number is stable; the authorization behind it is not.
Edge cases that change where you look
Name mismatches are the most common edge case. If the name on your airline reservation differs from the name on your trusted traveler record, the Secure Flight match fails and no PreCheck indicator prints. The number was correct; the identity match was not. Fix the booking name, not the number.
Program transfers create a second edge case. If you hold more than one program, you may have more than one identifier, and entering the wrong one can fail silently. Use the number from the program whose membership is active and whose name matches the booking.
Children and family members have their own records. A child approved under a family application still receives an individual identifier, and it must be entered on the child's own reservation. Copying a parent's number onto a child's booking does not work.
Card damage and fading print are practical edge cases, especially on older cards. When the back of a Global Entry card is scuffed, the account record is the reliable source. Photograph the account page rather than the card.
Red flags to watch for
A number that fails on every booking despite a correct name usually signals a lapsed membership, not a typo. Emails asking you to "confirm your Known Traveler Number" by clicking a link are phishing attempts; the government does not request the number this way. Third-party sites charging a fee to "retrieve" your number are unnecessary; the official account is free. A booking agent who cannot explain why PreCheck did not print is a signal to verify the name field yourself. A number shared in a group chat or public forum should be treated as compromised for privacy purposes.
Misconceptions worth correcting
The most persistent misconception is that the Known Traveler Number guarantees TSA PreCheck on every flight. It does not. The number makes you eligible; the airline's Secure Flight query and the matching rules decide whether the indicator prints. Eligibility and outcome are different things.
A second misconception is that the card number and the account number are interchangeable across programs. They are usually the same within a program, but travelers who hold multiple programs frequently mix them up. The account dashboard removes the ambiguity.
A third misconception is that the number is secret in the way a password is. It is an identifier, not an authenticator. Still, it links to your identity record, so treat it as personal information and avoid posting it publicly.
The counterintuitive professional caveat: a correctly entered number can still produce no PreCheck indicator because of random exclusion in the screening process. The program does not promise a screening outcome on any given trip, and no number entry can override that.
A comparison of where the number lives
| Source | Reliability | Best use |
|---|---|---|
| TTP account dashboard | Highest | Authoritative lookup after loss |
| Approval email | High | Quick reference at booking |
| Application confirmation screen | Medium | First-time capture |
| Physical card (back for Global Entry) | Medium | In-person reference |
| Physical card (front for NEXUS) | Medium | In-person reference |
| Airline profile saved field | Variable | Convenience, verify annually |
The practical rule is to trust the account dashboard over every other source. Cards fade, emails get buried, and airline profiles go stale after a name change.
Practical actions
Start by logging into your Trusted Traveler Programs account and confirming the number is displayed. Save a screenshot to a secure location, not a public cloud folder. This takes two minutes and removes the most common lookup failure.
Enter the number in your airline loyalty profile once, then verify it against a test booking. Airlines store the field per passenger, and a saved number does not automatically apply to companions.
For a family, create a checklist with each traveler's name and number side by side. Enter them individually at booking. This prevents the parent-number-on-child-booking error.
If PreCheck does not print, check the name field before re-entering the number. Middle names, suffixes, and hyphenation cause most match failures. Correct the booking name and re-check in.
For renewals, set a reminder roughly 60 days before expiration. Most programs allow early renewal, and a lapsed record suspends eligibility even when the number is unchanged.
Limits and what the number cannot do
The Known Traveler Number cannot speed up a security line by itself, cannot substitute for a passport, and cannot override a random exclusion. It is an eligibility key, not a guarantee. Travelers who expect otherwise are usually disappointed at the airport rather than at the booking screen.
The number also cannot fix a name mismatch or a lapsed membership. Those require the underlying record to be corrected. And it does not grant entry to any country; it only supports the trusted traveler screening pathway for departures from participating airports.
Formatting details vary by card revision and program, so the printed label wording is not a reliable identifier. The account record is. When in doubt, look there first.
This article is general educational information about a government traveler program, not a legal opinion or a guarantee of screening outcomes. Program rules, card designs, and eligibility criteria can change, so confirm current details with the official Trusted Traveler Programs source or a qualified travel professional before relying on them.