If your phone is ever lost, or stolen, it is possible to have your phone prevented from being used by anyone else.

This is done by contacting your network provider, telling them your phone IMEI number, and asking that it be prevented from use.

Preventing your phone from being used by unauthorised people is often referred to as blocking.

What do the letters IMEI stand for ?

International Mobile Equipment Identity

What is IMEI ?

IMEI is a unique number which identifies your phone.

You can use your IMEI number to prevent use of your phone in the event that it is lost or stolen. Preventing your phone from being used in that country, even if the SIM card is changed.

However, it pays to be aware that your phone could still be used in another country.


The IMEI number only relates to your phone (handset) and does not relate in any way to the SIM card within your phone.

Your IMEI number is typically 15 digits long.

Sometimes your IMEI number is referred to as IMEISV - International Mobile Equipment Identity Software Version - in which case your number will typically be 16 digits long.


Over time the make up of your IMEI, or IMEISV, number has changed, although the number of digits has remained the same.

Typically, the overall number consists of, in this order:

TAC - Type Approval Code, or Type Allocation Code - this, until 2004, comprised the first 6 digits;

FAC - Final Assembly Code - this comprised the next 2 digits;

SN - Serial Number - comprising the next 6 digits;

SP - Spare - the final  digit.

Between 2002 and 2004 the FAC sector was phased out - during this phasing out period the FAC digits were normally set to 00.

From 2004, the FAC sector had been completely phased out and the TAC sector then became 8 digits long.

Where your IMEI number includes a Software Number, this will be the final digit of a 15 digit number.

The overall IMEI number can be presented in a number of ways.

Typically, either 15 continuous digits, or as groups: 6 digits space 2 digits space 6 digits, space, 1 digit.

How do I find my phone IMEI number ?

There are two places, or ways, to find your phone IMEI number:

  • Printed inside the battery compartment;
  • By dialing (on the phone you want to find the IMEI number for) *#06# (Star hash number-zero number-six hash) - your phone IMEI number will then be displayed on your phone screen almost instantly after pressing the final #. You do not necessarily need to press the 'send' or 'call' button as you would do when making a telephone call.

It can be a very good idea to keep a record of your Phone IMEI number separate from your phone so that in the event your phone is lost, or stolen, you can report the IMEI number to the Network provider.

For this reason, it is also a good idea, if sending a Mobile Phone to a friend or colleague, take a note of the IMEI number so that if the phone becomes lost in transit a lucky finder does not become the "owner" of a free phone.


Changing, or attempting to change, your own, or any other mobile Phone IMEI number is a criminal offence except under certain circumstances.

For more information on Blocking, and Blocked phones, please read our article Blocked and Blocking.

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Tim Austin writes articles about various aspects of the Mobile Phone industry.

More articles are available by visiting www.SIMsurprise.co.uk