Updated November 11, 2026

Known Traveler Number (KTN): What It Is and How to Find Yours

A Known Traveler Number (KTN) is the code the Transportation Security Administration issues to travelers approved for TSA PreCheck expedited screening. For standalone TSA PreCheck members, TSA says your KTN is 9 or 10 digits long, can be a combination of numbers and letters, and starts with TT, TE, or AC. For Global Entry, NEXUS, and SENTRI members, your KTN is your 9-digit U.S. Customs and Border Protection PASSID, which you must enter into your airline reservation so the TSA PreCheck indicator prints on your boarding pass.

Which number is my KTN? Every program compared

Airlines call the field "Known Traveler Number" on every booking screen, even when your membership card or approval notice uses a different name for the number.

This table shows which number acts as your KTN, what it looks like, and where it is printed for each Department of Homeland Security (DHS) and partner program, according to TSA and CBP guidance. If you are still deciding which program to join, compare eligibility in our guides to Global Entry vs TSA PreCheck and NEXUS vs Global Entry.

Which number to enter in the airline Known Traveler Number (KTN) field by program

What is a Known Traveler Number and how does it work?

A Known Traveler Number links your flight reservation to your approved status for TSA PreCheck expedited screening. At more than 290 U.S. airports and across over 85 participating airlines, TSA PreCheck lanes let approved passengers keep on their shoes, belts, and light jackets, and leave laptops and 3-1-1 liquids inside their carry-on bags. According to TSA, about 99% of TSA PreCheck passengers wait less than 10 minutes at the checkpoint.

When you enter your KTN into your flight reservation or airline frequent flyer profile, TSA's Secure Flight System checks that number against your full name and date of birth. Once verified, the airline prints a TSA PreCheck indicator such as TSAPRECHK, TSA PRE, or TSA PreCheck directly on your boarding pass.

Physical cards do not open the lane. Both TSA and CBP state that you cannot walk up to a TSA PreCheck checkpoint and show a Global Entry, NEXUS, or SENTRI card, a TSA PreCheck approval notification, or a military Common Access Card (CAC) to get in. Standalone TSA PreCheck members do not receive a physical card. The indicator must be visible on your boarding pass when you fly domestically, depart from a U.S. airport to a foreign country, or take domestic connecting flights after returning to the United States.

How to find your Known Traveler Number if you forgot it

Where you look up a lost or forgotten KTN depends on which program gave you TSA PreCheck eligibility. Standalone TSA PreCheck accounts and CBP Trusted Traveler accounts use two separate government systems.

For the standalone TSA PreCheck Application Program, you do not use Login.gov. Most applicants receive their Known Traveler Number in 3-5 days after their in-person appointment, though some applications can take up to 60 days.

For Global Entry, NEXUS, or SENTRI, your KTN is your 9-digit membership number. If you are preparing for your enrollment appointment, see our Global Entry interview guide. You only receive TSA PreCheck benefits once you are approved after your interview, though CBP notes your membership number is also printed on your conditional approval letter.

• TSA PreCheck provider login: Log into your account on the website of the authorized enrollment provider you used: CLEAR, IDEMIA, or Telos.
• TSA KTN Lookup Tool: If you do not remember which enrollment provider you used, use TSA's KTN Lookup Tool on the TSA PreCheck website to find your active KTN, expiration date, and provider.
• Back of your Global Entry, NEXUS, or SENTRI card: Flip your card over to the upper-left corner. CBP Help states your number is the 9 numbers before SC.
• Trusted Traveler Programs (TTP) Dashboard: Sign in to the DHS Trusted Traveler Programs website with your Login.gov account to view your membership number on your TTP Dashboard.
• CBP Support portal: If you do not possess a membership card or are a previous CBP Trusted Traveler member, the TTP FAQ instructs you to submit an email inquiry through the CBP Help web support portal with your full name, date of birth, and place of birth.
• Saved frequent flyer airline profiles: Check the traveler profile section of any airline frequent flyer account, employer booking system, or online travel website where you previously saved your KTN.

Military, DoD civilian, TWIC, and HAZMAT Known Traveler Numbers

Several military and transportation credentials include TSA PreCheck expedited screening without a separate application or fee. Instead of a TT, TE, or AC code, you enter a number from your existing credential into the airline's KTN box.

U.S. Armed Forces and Uniformed Service Members: Active-duty armed forces members, Reserve components, National Guard (Army and Air), U.S. Coast Guard and Coast Guard Reserve, students at the U.S. military service academies (USMA, USNA, USAFA, USCGA, and USMMA), the U.S. Public Health Service (USPHS) Commissioned Corps, and the NOAA Commissioned Officer Corps receive free TSA PreCheck for duty and personal travel. Your KTN is the DoD ID number on the back of your Common Access Card (CAC). Armed forces members do not need to opt in. Enter your DoD ID in the KTN field of your reservation and in your Defense Travel System (DTS) profile.

DoD Civilian Employees: Federal civil service employees and non-appropriated fund (NAF) civilians also use their DoD ID number as their KTN for duty and personal travel. Before your DoD ID works as a KTN, TSA requires DoD civilians to complete a one-time opt-in at the ID Card Office Online (via milConnect) by logging in, selecting "My Profile", and choosing the "CIV" menu tab.

Leaving the Military or DoD: Free DoD TSA PreCheck benefits end when you retire or leave the DoD. Retirees, veterans, and non-DoD affiliated adult military dependents age 18 and over must enroll in a trusted traveler program to get their own KTN. TSA notes that military spouses qualify for a reduced enrollment or renewal fee, and military survivor families and qualifying severely disabled veterans under the VETS Safe Travel Act can enroll or renew at no cost.

TWIC and HAZMAT Endorsement (HME) Holders: Eligible TWIC cardholders (including U.S. citizen and lawful permanent resident cadets at the U.S. Merchant Marine Academy and six State Maritime Academies) enter their 8-digit Credential Identification Number (CIN) as their KTN, found under the bottom left of the barcode on the back of the TWIC card (and embossed on the front of the newest version). Eligible CDL holders with an active HME security threat assessment enter their issuing state's 2-letter abbreviation followed by their CDL number (such as NY123456). If you obtained your TWIC or HME through a TSA waiver, you are not eligible for TSA PreCheck.

How to add your KTN to airline profiles and family bookings

TSA PreCheck benefits are not automatic. Save your KTN in every place you book flights so you do not have to type it in each time. If you already booked a flight before you got your KTN, TSA says to contact your airline online or by phone to add it to the existing reservation. If you have both standalone TSA PreCheck and Global Entry, NEXUS, or SENTRI, DHS's TTP FAQ instructs you to use your Pass ID as your KTN.

Adults age 18 and older must have their own KTN to use TSA PreCheck lanes. For children 17 and under traveling with a PreCheck-eligible parent or guardian, TSA divides the rules by age. Note that CBP states Global Entry customs lanes are member-specific: children cannot join you in the Global Entry lane on arrival into the U.S. unless each child has their own membership. Since October 1, 2024, children under 18 can enroll in Global Entry, NEXUS, or SENTRI free of charge when a parent or legal guardian is already an enrolled member or has a pending or conditionally approved application.

• Where to save your KTN: Add your KTN to your airline frequent flyer profiles, employer booking systems, Defense Travel System (DTS) profile, online travel websites, and individual flight reservations alongside your exact full name and date of birth.
• Children 12 and under: Can accompany an eligible adult through TSA PreCheck lanes for free. The TSA PreCheck indicator does not need to appear on the child's boarding pass.
• Children 13-17: Can join you in the TSA PreCheck lane only when the TSA PreCheck indicator appears on the child's boarding pass. When the teen does not have their own KTN, TSA says you must book the teen on the same airline reservation as the PreCheck-eligible adult and leave the teen's KTN field blank. If booked on a separate reservation, they need their own KTN.
• Unaccompanied minors and gate passes: Unaccompanied minors in TSA PreCheck lanes must show an acceptable ID. Parents escorting a child through security with an airline gate pass are directed to standard screening even if the parent has TSA PreCheck.

Why TSA PreCheck did not print on your boarding pass (8-step checklist)

If you added your KTN to your ticket but checked in and found no TSA PreCheck indicator on your boarding pass, work through this troubleshooting checklist written by our team from TSA and CBP rules:

1. Check for a middle name, hyphen, or apostrophe mismatch: TSA states that the name on your airline reservation must exactly match the name on your application. If you included your middle name on your application, include it on the flight reservation. If your name has a hyphen (such as Billings-Smith) or an apostrophe (such as O'Sullivan), put your first, middle, and last names in the matching boxes.

2. Check your date of birth and KTN digits: A mistyped digit in your KTN or birth date stops TSA's Secure Flight System from verifying your record.

3. Confirm your KTN has not expired before travel day: TSA warns that if you book a flight while your KTN is active, but the flight takes place after your KTN expires, you will not get TSA PreCheck on your boarding pass.

4. Make sure you updated any legal name change: TSA PreCheck name changes through your enrollment provider can take up to 45 days. CBP Trusted Traveler name changes require visiting an Enrollment Center or submitting a color image of your current passport photo page through the CBP Help web support portal.

5. Check that your airline and airport participate: Over 85 airlines and 290+ airports participate, but non-partner carriers cannot print the indicator.

6. Verify citizenship rules for NEXUS and SENTRI: All Global Entry members get TSA PreCheck. For NEXUS, only U.S. citizens, U.S. lawful permanent residents (LPRs), and Canadian citizens are eligible. For SENTRI, only U.S. citizens and U.S. LPRs receive TSA PreCheck.

7. Confirm DoD civilian opt-in or active DoD status: DoD civilians must opt in once at the ID Card Office Online (milConnect). If you retired or separated from the military or DoD, your DoD ID stops working for PreCheck.

8. Account for recurrent vetting or random security measures: TSA uses unpredictable security measures, and no individual is guaranteed expedited screening. Enrollees also undergo recurrent criminal history vetting. New criminal records can cause a temporary suspension (typically under 30 days, up to 90 days), while federal security violations can cause a suspension of up to 5 years or permanent disqualification.

If you check all eight items and still do not receive the indicator, TSA asks you to reach out within 72 hours of the issue. Text "Travel" (275-872) to AskTSA for live assistance from 8 a.m. to 6 p.m. ET, message @AskTSA on X or Facebook Messenger, use Apple Business Chat, or call the TSA Contact Center at (866) 289-9673 (8 a.m. to 11 p.m. ET weekdays and 9 a.m. to 8 p.m. ET weekends and holidays).

Does your KTN change when you renew or switch programs?

Renewing TSA PreCheck: TSA confirms that you keep your exact same Known Traveler Number when you renew your TSA PreCheck membership, even if you switch to a different enrollment provider (CLEAR, IDEMIA, or Telos). IDEMIA and Telos each operate 500+ active locations and CLEAR operates 348 active locations. You can renew online up to 6 months before your expiration date, and the new 5-year period starts when your current one ends. TSA recommends renewing at least 60 days before expiration.

Renewing Global Entry, NEXUS, or SENTRI: Log in to your TTP account associated with your membership number starting 1 year before your expiration date and pay the non-refundable 5-year renewal fee on the DHS Trusted Traveler Programs website. If you submit your renewal application before your current membership expires, CBP extends your active benefits for up to 24 months after your expiration date while your renewal is processed. Read our Global Entry renewal guide for the steps.

Switching from TSA PreCheck to Global Entry: TSA states that you cannot upgrade or transfer a standalone TSA PreCheck membership into Global Entry. You must apply for Global Entry as a new applicant on the DHS Trusted Traveler Programs website. Provide your current 9 or 10 digit TSA PreCheck KTN on the Global Entry application, which may make you eligible for expedited Global Entry processing. Here is our team's 3-stage timeline for which KTN to keep in your airline profiles during the switch:

• 1. Application Pending Review: Vetting normally occurs within 2 weeks, though manual review takes 12-24 months. Keep your unexpired TT, TE, or AC number in all flight bookings while your application is pending.
• 2. Conditionally Approved: You have 2 years to complete your in-person interview at an Enrollment Center or through Enrollment on Arrival. TSA states you will not receive TSA PreCheck through Global Entry until your Global Entry application is approved, so keep using your unexpired standalone TSA PreCheck KTN.
• 3. Approved after interview: CBP typically approves your application within 1-2 business days after your interview, activating your 5-year membership. New members receive their Global Entry card in 2-4 weeks, and you can immediately update your airline profiles to use your Pass ID as your KTN.

KTN vs Redress Number, Reconsideration, and REAL ID

KTN vs Redress and Reconsideration: Within TSA PreCheck, TSA defines redress as the process for people who were incorrectly disqualified from TSA PreCheck, such as a false match to another person or a disqualification that lasted longer than intended, which entitles you to get your lost membership time back. Reconsideration is for people who committed a regulatory violation and ask TSA to reconsider the length of their disqualification.

KTN vs REAL ID: Having a KTN does not replace physical identification at the airport. Both TSA and CBP state that since May 7, 2025, all adult travelers, including TSA PreCheck members, must present a REAL ID-compliant state driver's license or another acceptable form of ID (such as a valid passport, or a physical Global Entry, NEXUS, or SENTRI card) at the TSA checkpoint.

Practice example

Have any of your personal details, addresses, employment history, or travel documents changed since you submitted your Trusted Traveler application?

Example preparation guide written by our team. Because CBP does not allow you to edit your online Trusted Traveler application once you certify and pay, the enrollment interview is your dedicated moment to correct any errors or update changed facts before your 9-digit PASSID is activated as your Known Traveler Number. Start by telling the officer clearly whether your details are unchanged or if you need to update a specific item, such as a new residential address, a renewed passport, a recent legal name change, or a mistake you noticed after submitting. Have your original supporting documents out and ready to hand over: every valid passport you travel with, your permanent resident card with a machine-readable zone if applicable, and proof of your current residence such as an updated driver's license, mortgage statement, rental payment statement, or utility bill. If you have ever been fingerprinted for an arrest or incident, bring the certified court disposition documents even if the record was expunged. State the exact update briefly so the officer can enter the accurate spelling and document numbers into your profile.

The CBP officer is verifying your identity, residence, and low-risk eligibility against your application and law enforcement databases. Giving clear updates with original documents ensures your TTP profile matches your passport and airline reservations so your PASSID works smoothly for TSA PreCheck.

Related guides

• Global Entry vs TSA PreCheck
• NEXUS vs Global Entry
• Global Entry interview guide
• Global Entry renewal guide

This is interview practice, not legal advice. For questions about your own case, talk to an immigration attorney. Visaful is not affiliated with the U.S. government or the Department of State.