What is an IMEI number?

Even though the IMEI number has been a vital part of mobile equipment as a device identifier, the interest in IMEI has grown over time, especially as smartphones became more popular. Thanks to the iOS and Android platforms, it has become a lot easier than before to find device information, including IMEI numbers. IMEI is a crucial piece of information for all cellular devices. This post will dive into the definition and use of IMEI, explain what it stands for, show you what it looks like, and answer some other inter-related questions. If you have any further questions, please feel free to use the comments section to share your views.

What does IMEI stand for?

IMEI stands for International Mobile Equipment Identity, and it is a unique fifteen digit number assigned to every cellular device for each of its SIM slots. Cellular devices like smartphones are SIM-enabled which means you have to put in a SIM card to connect them to the network. We have multiple SIM options in newer mobile phones, including a physical compartment for slotting in a plastic SIM and an embedded SIM called eSIM inside the phone that you can manually assign to a mobile network. The IMEI number is unique to every cellular connection; therefore, if you have a dual-SIM phone (a phone that can take two SIMs), whether plastic or electronic, your phone will have two IMEI numbers. More about eSIM in this dedicated post.

What does an IMEI number look like?

The IMEI number is a 15 digit code, all numeric, which shows up on all mobile phones in the same number format. However, the user interface (UI) design may differ depending on the device manufacturer and operating system. Below some pictures to show you exactly what the IMEI number looks like on smartphones.

what is imei number
Example: IMEI number displayed on a Huawei Android phone (We have updated the screenshot to replace the actual IMEI)
Example of how IMEI is displayed on an iPhone (We have updated the screenshot to replace the actual IMEI)
Example of how IMEI is displayed on an iPhone (We have updated the screenshot to replace the actual IMEI)
Example: IMEI number displayed on an old Samsung Android phone (We have updated the screenshot to replace the actual IMEI)
Example: IMEI number displayed on an old Samsung Android phone (We have updated the screenshot to replace the actual IMEI)

How can I check my IMEI number?

There are multiple ways of checking IMEI numbers. The best way to check your IMEI number is to type a sequence *#06# on the dial-pad of your cell phone, which will display the IMEI number on the phone screen. You can also check the IMEI number by going into the ‘Settings’ menu on your phone. For iPhones, you need to go to “Settings”–> “General” –> “About” and then scroll down to find your IMEI number. For Android phones, generally, you can go to “Settings”–>”About phone” to find the IMEI number. You can also check the IMEI number on other devices like SIM-enabled tablets, smartwatches and cellular mobile broadband routers. Check out this dedicated post to learn some ways of checking the IMEI number on your cellular devices.

What is the IMEI number used for?

The IMEI number is a unique device identifier that lets mobile operators know which device is trying to access the mobile network. Unlike IMSI (International Mobile Subscriber Identity), which is a SIM-specific identifier, IMEI is unique to the device itself. If a mobile phone gets lost or stolen, the IMEI number is the way to block the handset from being misused. As a mobile phone user, if you lose your phone for whatever reason, you need to ensure that you contact your mobile operator to block the IMEI and IMSI because IMEI is specific to your device, and IMSI is specific to your SIM. IMEI number allows an operator to place a specific mobile phone on a blacklist which means the phone is prohibited from accessing the mobile network no matter which SIM is inside it. The device registration and tracking capability reside within the mobile core network. Equipment Identity Register (EIR) is the entity within the mobile core network that stores the IMEI information in a database. You can check out this post if you need more information about the difference between IMSI and IMEI.

Can someone track you with your IMEI number?

Yes. IMEI number is the identifier of cellular devices and is linked to the device itself irrespective of which subscription (SIM) it uses. So, for example, if someone steals your phone and discards the SIM card, the IMEI number will still allow a mobile network to track your mobile phone. IMEI is one of the device identifiers the police in some countries use to track cell phones in collaboration with mobile operators. On the other hand, if you are concerned that any random person may start tracking you simply because they know your IMEI number, that is not as simple. Unless this random person has installed an IMEI tracking app on your mobile phone (which makes it very easy to track), their only option is to work with your mobile operator to track you. Mobile operators do not give out IMEI numbers randomly and follow a rigorous security process to ensure that your personal information is only available to authorised individuals. As a disclaimer, this is my personal opinion based on my telecom background, and therefore not professional advice. You should always contact your mobile operator or service provider for any professional advice regarding your phone or subscription.

Should you give your IMEI number to anyone?

IMEI number can be misused, which is why you should only share it with those you trust, e.g. your mobile operator. There may be occasions when your mobile operator may request the IMEI number of your device for enabling/disabling services, e.g. unlocking your phone. If your IMEI gets into the wrong hands, misuse can potentially happen. Even though the IMEI number is unique and stays with the mobile device for its lifecycle, it is technically possible for someone (with special tools) to alter it. Making any modification to the IMEI number is called “unblocking”, which is a criminal offence under UK laws. If someone with bad intentions gets hold of your IMEI number, and if they have access to special tools to modify the IMEI of a cellular device being used for illegal activities, your IMEI number can be at the risk of becoming a scapegoat.


In summary, IMEI stands for International Mobile Equipment Identity, and it is a 15 digit unique number assigned to every cellular device for each SIM slot. If you have a dual SIM, your phone will have two IMEI numbers, one for each SIM slot. IMEI is a device-specific identifier, and even if a user swaps SIM cards, the IMEI of the device stays the same.

Here are some helpful downloads

Thank you for reading this post, I hope it helped you in developing a better understanding of cellular networks. But sometimes, we need some extra support especially when preparing for a new job, or studying a new topic, or maybe just buying a new phone. Whatever you are trying to do, here are some downloads that can help you:

Students & fresh graduates: If you are just starting, the complexity of the cellular industry can be a bit overwhelming. But don’t worry, I have created this FREE ebook so you can familiarise yourself with the basics like 3G, 4G etc. As a next step, check out the latest edition of the same ebook with more details on 4G & 5G networks with diagrams. You can then read Mobile Networks Made Easy which explains the network nodes e.g. BTS, MSC, GGSN etc.

Professionals: If you are an experienced professional but new to mobile communications, it may seem hard to compete with someone who has a decade of experience in the cellular industry. But not everyone who works in this industry is always up to date on the bigger picture and challenges given how quickly the industry evolves. The bigger picture comes from experience which is why I’ve carefully put together a few slides to get you started in no time. So if work in sales, marketing, product, project or any other area of business where you need a high-level view, Introduction to Mobile Communications can give you a quick start. Also, here are some templates to help you prepare your own slides on product overview and product roadmap.

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