What Is IMEI? Complete Guide to IMEI Numbers
IMEI is the unique "ID card" for every mobile phone. Understanding what IMEI means, its structure, and how to use it can help you verify a device's authenticity, lock status, and purchase history.
IMEI Definition and Meaning
IMEI (International Mobile Equipment Identity) is a globally unique 15-digit identification number assigned by the GSMA (Global System for Mobile Communications Association) to every compliant mobile device that connects to cellular networks. Each phone, tablet with cellular capability, or mobile hotspot receives a unique IMEI during manufacturing.
Think of IMEI as a phone's "passport number." Just as a passport identifies an individual's nationality and identity, an IMEI identifies a device's manufacturer, model, production batch, and compliance status. When carriers, manufacturers, or law enforcement need to track a device, the IMEI is the most authoritative reference.
IMEI 15-Digit Structure Explained
The 15 digits of an IMEI are not random β they follow a strict, meaningful structure:
- TAC (Type Allocation Code, first 8 digits): Licensed by GSMA to manufacturers. Identifies the specific device model. For example, the iPhone 15 Pro Max and Samsung Galaxy S24 Ultra have different TAC segments.
- SNR (Serial Number, digits 9-14): Assigned by the manufacturer to uniquely identify each unit within the same model. These 6 digits ensure every device has a distinct IMEI.
- CD/Spare (Check Digit, 15th digit): Calculated using the Luhn algorithm to validate the first 14 digits. A mismatched check digit indicates an invalid or tampered IMEI.
When you perform an IMEI check on IMEICheck, the system first validates the IMEI structure before cross-referencing it with GSMA and manufacturer databases to ensure accuracy.
How to Find Your Phone's IMEI
Finding your IMEI is straightforward using any of these methods:
- Dial Code (Fastest): Open the phone dialer and enter
*#06#. The IMEI will immediately appear on screen. Dual SIM phones typically show both IMEI 1 and IMEI 2. - System Settings: iPhone β "Settings β General β About". Android β "Settings β About Phone β Status".
- Physical Label: Check the original packaging box, the SIM card tray (certain iPhone models), or the sticker on the back of the device. Purchase receipts and email confirmations also typically include the IMEI.
- iTunes/Finder (iPhone): Connect your iPhone to a computer and view the IMEI in iTunes (Windows) or Finder (Mac).
We recommend saving your IMEI in a secure location. If your device is lost, the IMEI is essential information for reporting to your carrier and law enforcement.
Real-World Uses of IMEI
Understanding IMEI isn't just about knowing a number β it has multiple practical applications:
- Theft Prevention & Tracking: Report your IMEI to your carrier if your phone is lost. The carrier will add it to the device blacklist, rendering it unusable on any participating network. While IMEI alone cannot pinpoint a phone's location, it is a critical clue for law enforcement.
- Warranty Verification: Apple, Samsung, Xiaomi, and other brands identify warranty status through IMEI or serial number. Enter your IMEI to see whether your device is under warranty and the coverage expiration date.
- Carrier Lock Detection: Some contract phones are locked to a specific carrier. An IMEI check clearly shows whether the device has a SIM lock and which carrier it originally belonged to β vital information when buying a used phone.
- Used Phone Verification: Before purchasing a secondhand phone, run the IMEI through IMEICheck to check its blacklist status, activation lock status, and whether it's a refurbished device.
IMEI vs MEID vs Serial Number
| Identifier | Format | Scope |
|---|---|---|
| IMEI | 15 digits | Global GSM/UMTS/LTE devices |
| MEID | 14 hex digits | CDMA devices (select US carriers) |
| Serial Number | Varies by brand | All devices (warranty and parts tracking) |
In short: IMEI is the international network identifier managed by GSMA; MEID is the CDMA network identifier; and the serial number is the manufacturer's internal production identifier. For most use cases, the IMEI is sufficient for device verification on IMEICheck.
Frequently Asked Questions
Q1: What does IMEI stand for?
IMEI stands for International Mobile Equipment Identity. It is a 15-digit number that uniquely identifies every mobile device on cellular networks.
Q2: Can IMEI be changed?
Technically yes via specialized tools, but this is illegal in most countries. Altered devices lose warranty and may be remotely locked. IMEICheck can detect IMEI-hardware mismatches.
Q3: Is IMEI globally unique?
Yes. GSMA's TAC and serial number allocation ensures no two devices worldwide share the same IMEI.
Q4: How to verify IMEI authenticity?
Use IMEICheck to validate the IMEI check digit and cross-reference with GSMA and manufacturer databases to confirm device model and production details.
Q5: What is IMEI used for?
IMEI is used for theft prevention (carrier blacklisting), warranty checks, carrier lock detection, and used phone verification before purchase.
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