Find Your KTN Number Information Guide

What Is a KTN Number and Why You Might Need One

A KTN number — short for Known Traveler Number — is an identifier issued by the U.S. Transportation Security Administration (TSA) that connects your identity to certain security screening programs at airports. If you've heard someone mention their "known traveler number" at check-in or seen it requested on airline websites, you've encountered this system. It's not a government ID card or driver's license replacement; rather, it's a code that lives in your TSA profile and communicates with airline reservation systems.

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The KTN acts as a bridge between you and trusted traveler programs. When you enroll in programs like TSA PreCheck, Global Entry, NEXUS, or SENTRI, you receive a KTN as part of that enrollment. This number tells airport screeners that you've undergone additional vetting and background checks, which can result in shorter security lines and a streamlined screening process at participating airports.

Here's the practical reality: not everyone needs a KTN number. If you fly occasionally and don't mind standard security screening, you may never encounter this system. But if you travel multiple times per year — for work, family visits, or vacations — having a KTN can reduce the friction of airport procedures. Business travelers especially benefit, as they might pass through security 20 or 30 times annually.

The TSA reported that as of 2023, over 12 million people held active TSA PreCheck memberships alone, representing roughly 3% of the U.S. flying population. That number continues to grow as more travelers discover the value of faster screening.

Practical takeaway: Determine whether you travel frequently enough to warrant exploring a trusted traveler program. If you fly two or more times per year on average, the investment and process of obtaining a KTN may pay dividends in time saved and reduced travel stress.

Understanding the Different Trusted Traveler Programs

The U.S. government operates several distinct trusted traveler programs, and each one issues its own KTN. Understanding the differences matters because the program you choose affects the airports where your KTN works, the countries your number covers, and the cost of membership.

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TSA PreCheck is the most widely used program domestically. It costs $78 to $85 for five years and provides expedited screening at over 200 U.S. airports. When you use your KTN at the airport, you typically keep your shoes on, leave your belt on, and keep your laptop in your bag during the security checkpoint. This program focuses entirely on domestic travel within the United States.

Global Entry is broader in scope and costs $100 for five years. It covers TSA PreCheck benefits for domestic flights plus expedited customs and immigration processing when you return to the United States from international travel. If you travel internationally even occasionally, Global Entry represents a significant time-saver at customs, where you can use kiosks for faster processing instead of waiting in general lines.

NEXUSSENTRI serve specific geographic populations. NEXUS ($120 for five years) streamlines travel between the U.S. and Canada, while SENTRI ($122.50 for four years) focuses on U.S.-Mexico border crossings. Both programs include TSA PreCheck benefits as well, meaning your KTN works for domestic flights regardless of which program you join.

A critical detail many travelers overlook: you can hold multiple trusted traveler memberships simultaneously. Some people enroll in both Global Entry (for international trips) and NEXUS (for frequent Canada visits), for example. Each membership issues its own KTN, but you'll typically use one primary number when flying domestically.

Practical takeaway: Map your typical travel patterns over the next five years. Are most of your trips domestic? Do you cross into Canada or Mexico regularly? Does international travel happen at least annually? Your answers determine which program makes financial sense and, consequently, which KTN you'll use most often.

How to Locate Your KTN If You Already Have One

If you've enrolled in a trusted traveler program, your KTN is already issued and associated with your TSA account. The challenge is simply finding where it's stored, since many people receive their KTN and then don't think about it until they need it months later.

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Your first option is to visit the official TSA website at tsa.gov and log into your account through the "TSA PreCheck" section. Once you're logged in with your username and password, you'll see your personal profile. Your KTN appears prominently near the top of your account information — it's typically a nine-digit number. Write this down or take a screenshot, as you'll reference it during airline check-in.

Your second option is to contact the TSA directly. The TSA Customer Service phone line operates at 1-866-289-9673, and representatives can retrieve your KTN if you provide your name, date of birth, and passport number (if applicable to your program). Wait times vary; calling during mid-morning on a Tuesday or Wednesday typically results in shorter hold times than calling on Friday afternoons.

Your third option involves checking your email archives. When you completed your trusted traveler program enrollment and final interview, you received a confirmation email. This email included your KTN in the body text or as an attachment. If you have access to the email account you used during enrollment, search for messages from TSA or the enrollment provider (companies like Idemia and Telos manage enrollment appointments).

Many travelers discover their KTN by checking their airline frequent flyer accounts. If you've already entered your KTN in an airline's reservation system before, that airline has it on file. Log into your account with American, United, Delta, Southwest, or whichever carrier you use most, navigate to your profile or preferences section, and look for "Known Traveler Number" or "TSA PreCheck" fields. If you've entered it previously, it will display there.

Practical takeaway: Retrieve your KTN today and store it somewhere you can access it before flying — your phone notes, a password manager, or a document in cloud storage. Having it readily available means you can enter it during online check-in or provide it at the airport without fumbling through accounts or calling TSA.

Entering Your KTN During Airline Check-In

Once you have your KTN in hand, the next step is making sure the airlines you fly with actually know about it. This step gets missed frequently, and it's the reason why travelers sometimes don't experience the benefits of their trusted traveler status at the airport.

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Most airlines offer two windows for entering your KTN: during the booking process and during online check-in. When you search for and purchase a flight, some airline websites display a question asking for your KTN. If you see this field, enter your nine-digit number. Not all airline sites present this option at booking time, so don't worry if it's absent.

Online check-in is where KTN entry becomes almost universal. Within 24 hours of your flight departure, you can check in through the airline's website or app. During this process, you'll be asked about TSA PreCheck, Global Entry, or other trusted traveler status. Select "yes," and a field will appear asking for your KTN. Enter it exactly as it appears on your TSA account — no spaces, no dashes, just nine digits.

Here's where many travelers make a mistake: they assume entering their KTN in one airline's system means all airlines have it on file. This isn't true. Each airline maintains its own reservation system. If you fly Delta, United, and Southwest, you need to enter your KTN in each airline's system independently. The TSA doesn't share this information across airlines automatically.

If you're checking in at the airport counter (rather than online), you can provide your KTN to the agent when you present your identification. The agent will enter it into the system at that time. However, entering it yourself online beforehand is faster and more reliable, since you control the accuracy of the entry.

Your boarding pass may or may not display your KTN visibly; this depends on the airline and the version of your boarding pass. Some airlines print "TSA PreCheck" on your physical boarding pass, others indicate it digitally, and some don't mark it at all.