You have probably heard the term IMEI but may never have needed to look yours up. That changes the moment you want to verify a used phone, report a theft, or understand a device's history. This guide explains everything you need to know about IMEI numbers — what they are, what they contain, and what you can find out from one.
What Does IMEI Stand For?
IMEI stands for International Mobile Equipment Identity. It is a 15-digit number unique to every mobile device that contains a cellular modem — smartphones, tablets with SIM cards, mobile Wi-Fi hotspots, and some laptops with built-in cellular connectivity.
The key word is equipment — IMEI identifies the device (the hardware), not the SIM card or the account. This distinction matters: swapping a SIM card does not change the IMEI. The IMEI stays with the physical hardware for its entire life.
Where Does IMEI Come From?
IMEI numbers are allocated by the GSMA (Global System for Mobile Communications Association) — the international body that coordinates mobile standards globally. Manufacturers apply to the GSMA for blocks of IMEI numbers before manufacturing begins. Each device is then assigned one of these numbers during production, programmed into the device's firmware and written to a physical label.
The Structure of an IMEI Number
An IMEI is not a random 15-digit number — it is structured to carry specific information. Breaking down a typical IMEI:
35 609104 123456 7
Digits 1-2 (Reporting Body Identifier — RBI): The organisation that allocated the TAC. Most modern devices use 35 or 86, indicating GSMA allocation.
Digits 3-8 (Type Allocation Code — TAC): The remaining 6 digits of the 8-character TAC block. Together with the RBI, these 8 digits identify the device's manufacturer and model. Every iPhone 15 Pro Max has the same TAC prefix. Every Galaxy S25 Ultra has its own TAC prefix.
Digits 9-14 (Serial Number): The 6-digit production sequence number, unique to each individual device within that model. This is what makes every IMEI globally unique.
Digit 15 (Check Digit): Calculated using the Luhn algorithm applied to the preceding 14 digits. This final digit allows any system to verify the IMEI has not been accidentally corrupted or deliberately altered.
What an IMEI Can Tell You
This is where IMEI becomes practically useful. With a device's IMEI, you can query multiple databases to find out:
Device model and manufacturer The TAC code (first 8 digits) maps to a specific device model in the GSMA IMEI Database. An IMEI check returns the manufacturer (Apple, Samsung, Huawei, etc.), model name, and often detailed specifications. This lets you verify that a device being sold as one model is not actually a lower-spec alternative.
Carrier registration Carriers register IMEIs when devices are activated on their networks. A carrier lookup reveals which network originally sold the device and whether it is locked to that carrier.
Blacklist status Global blacklist databases record IMEIs of devices reported lost, stolen, or involved in fraud. A blacklisted IMEI cannot connect to participating carrier networks.
Warranty and coverage status For Apple devices, the IMEI links to AppleCare and warranty records. For Samsung, warranty registration uses the IMEI. For other brands, warranty data varies in availability.
Lock status iCloud Activation Lock (Apple), Factory Reset Protection (Android), Samsung Knox Guard, and Mi Account Lock (Xiaomi) can all be queried with an IMEI.
How to Find Your IMEI
Universal method (all phones): Dial *#06# — the IMEI appears on screen immediately. This works on every phone regardless of manufacturer.
iPhone and iPad: Settings > General > About > IMEI. Also on the SIM tray and original box.
Android: Settings > About Phone > Status > IMEI. Location varies slightly by manufacturer.
Original box: Every phone's IMEI is printed on the retail packaging as a barcode and in plain text.
Carrier account: Log in to your carrier account — the IMEI of devices on your account is typically visible in device management.
IMEI vs Serial Number — What's the Difference?
Both IMEI and serial number uniquely identify a device, but they serve different purposes:
- IMEI is a network identity, used by carriers and the GSMA to identify devices on mobile networks
- Serial number is a manufacturer's production identity, used internally for product tracking, warranty management, and device management
All cellular devices have both. Devices without cellular capability (iPad Wi-Fi, Apple Watch GPS, iPod Touch) have serial numbers but no IMEI.
IMEI and Privacy
Your IMEI is broadcast to mobile networks every time you connect. Carriers can log which cell towers your device connects to. Law enforcement can use this information with appropriate legal authority. This is by design — it enables stolen phone blacklisting and location assistance for emergency services.
Sharing your IMEI with a used phone buyer or a check service does not compromise your security in a meaningful way. The IMEI is not a password — it cannot be used to access your accounts or data. Be cautious about sharing it with unknown entities, but there is no concern with using it for legitimate verification checks.
IMEI2 — Dual SIM Phones
Phones with dual SIM capability (two SIM cards simultaneously) have two IMEIs — IMEI1 for the first slot and IMEI2 for the second. Both are displayed when you dial *#06#. When performing pre-purchase checks, checking the primary IMEI (IMEI1) is generally sufficient, though checking both ensures completeness.