What is an IMEI number?

The International Mobile Equipment Identity (IMEI) number is a unique identification or serial number that all mobile phones and smartphones have. It is usually 15 digits long.

As of 2004, the format is AA-BBBBBB-CCCCCC-D, although it may not always be displayed this way. It follows a carefully defined structure that reveals information about the device:

  • Type allocation code (TAC): The initial eight digits represent the device manufacturer and the specific model. The GSMA, an industry organization, allocates the TAC.
  • Serial number (SNR): The following six digits denote a unique serial number defined by the device manufacturer.
  • Check digit (CD): The last digit serves as a verification mechanism based on the Luhn algorithm. This mathematical formula detects any errors or mistyped numbers.

Dual-SIM phones (devices with two SIM card slots) have two separate IMEI numbers.

International Mobile Equipment Identity number types

  • IMEI: The standard, primary identifier for most cellular devices.
  • IMEISV: Includes an additional two digits for Software Version Number (SVN) to identify the device’s software.

What is the International Mobile Equipment Identity number used for?

IMEI numbers have one principal purpose – to identify the devices. The number is encrypted into the device rather than onto the SIM card, adding an extra layer of identification and security. No two phones have the same IMEI number.

If the device is lost or stolen, your carrier can blocklist the number and lock it out of the mobile network, making it harder for thieves to use the stolen device. Each country has its policy on how this works. It is important to note that only the carrier who issued the device has the legal right to block the IMEI number.

If you buy a secondhand phone, you can check its IMEI number using websites like IMEI.info. This tells you if it’s reported as stolen or has other issues.

It also reveals information about your phone, like the brand, model, and year it was made.

How do you find your IMEI number?

Physical location

May be printed on:

  • The back of the phone
  • Under the battery (older models)
  • The SIM card tray
  • The original packaging

Settings

If you own an Apple device, locate your International Mobile Equipment Identity number in the box where it came in or go to “Settings -> General -> About” and scroll down until you find the information.

If you own an Android phone, go to Settings menu -> About Phone -> Status -> IMEI Information.

Universal code

Another alternative for Apple and Android devices is to dial *#06#, and the information will appear on the screen.

Google Find My Device

If your phone is linked to your Google account, you can often find the number on the “Find My Device” website.

Changing or spoofing

While technically possible, changing your device’s International Mobile Equipment Identity number is generally illegal and strongly discouraged. Here’s why:

  • Network disruption: They are essential for networks to identify and track devices. Tampering risks causing interference.
  • Illegal activity: International Mobile Equipment Identity number spoofing is often used to mask stolen or counterfeit devices.
  • Loss of warranty: Manufacturers may void a device’s warranty with a modified IMEI.

IMEI vs. MEID vs. ESN

While IMEI is used on GSM networks, different standards existed on older CDMA networks:

  • MEID (Mobile Equipment Identifier): Similar, but with a slightly different structure, used on CDMA networks.
  • ESN (Electronic Serial Number): An older 32-bit identifier that predates MEID and IMEI.

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