What Is an IMEI? Structure, IMEISV and Luhn Limits

IMEI stands for International Mobile Equipment Identity. Mobile networks and equipment-management systems use it to distinguish cellular equipment. It identifies the equipment, not the subscriber account or the SIM profile.

The form normally shown to a user contains 15 decimal digits. The first 14 carry the allocated type and serial portions; the final digit is a Luhn check digit intended to catch manual entry errors. GSMA TS.06 documents the allocation rules and security requirements.

IMEI Structure

49015420 323751 8
└─ TAC ─┘ └SNR─┘ └ check digit
 8 digits 6 digits  1 digit

490154203237518 is a public format example used here only to demonstrate the checksum. It is not a lookup result or proof of a particular device.

Type Allocation Code: Digits 1-8

The TAC is allocated for a device type under the GSMA process. A marketed model can be associated with more than one TAC, and a production mapping requires current, appropriately licensed data. The first one or two digits alone do not identify a brand, country of manufacture or carrier.

Serial Portion: Digits 9-14

The six-digit serial portion distinguishes equipment within a TAC allocation. Allocation rules aim to prevent duplicate TAC-and-serial combinations, but a format checker cannot detect cloning, bad source data or a generated collision.

Check Digit: Digit 15

The final digit follows the Luhn formula. It helps detect common transcription errors. It does not authenticate the preceding digits and does not contact a device registry, carrier or block list.

IMEI, IMEISV, MEID, ICCID and IMSI

These identifiers belong to different layers. Treat them as separate fields instead of converting one into another without a documented contract.

Which Devices Have an IMEI?

Cellular-capable phones, tablets, hotspots, watches and embedded modems can have an IMEI. A Wi-Fi-only device does not need one for cellular-network registration. Samsung notes that identifiers and menu paths vary by product, and its Wi-Fi-only tablets do not show an IMEI. Apple distinguishes cellular iPads from Wi-Fi-only models in the same way.

Dual-SIM and eSIM-capable equipment can expose more than one IMEI. Do not assume a universal relationship between IMEI1, IMEI2, a physical slot and an eSIM profile; follow the documentation for the model and the contract of the system you are testing.

How to Find the IMEI on Your Device

Start with the settings page on the device:

• Apple documents Settings > General > About for iPhone and cellular iPad. Its support page also lists model-dependent locations in Finder, an Apple Account, packaging, a SIM tray or the device body.
• Samsung documents Settings > About phone for current Galaxy devices, with other locations depending on the model.
• Many phones display equipment identifiers when you enter *#06# in the dialer.

Packaging and account records can be useful when the phone is unavailable, but they are not present in every sale or device configuration. When inspecting a used phone, read the identifier from the device and compare other records rather than relying on one screenshot.

Avoid posting a complete IMEI publicly. An app rarely needs a non-resettable hardware identifier: Android's identifier guidance recommends using a more restricted, resettable identifier whenever the use case allows it.

What Systems Use an IMEI For

Depending on the operator, manufacturer and product, an IMEI can appear in:

• cellular equipment registration and device-status systems;
• enterprise inventory and authorized device-management feeds;
• support, repair or purchase records;
• lost/stolen reporting and block-list services.

An IMEI alone does not prove ownership, warranty, carrier compatibility, payment status or radio capability. Each conclusion needs the source that owns that information.

For a used device, follow the IMEI blacklist check guide, which links to official and industry-backed services by market. Random IMEI does not perform that lookup.

A QA Contract for IMEI Fields

A useful test suite separates syntax from external status:

In application code, define separate outcomes for malformed input, valid Luhn with unknown TAC, known local mapping, and status unavailable. Mock carrier or block-list responses. Do not send generated values to live identity services.

How Random IMEI Uses the Format

Random IMEI selects an eight-digit prefix from a dated, limited local snapshot, appends a pseudo-random six-digit serial and calculates the Luhn digit. This produces a structurally valid fixture for isolated tests.

The site does not query the GSMA Device Database, a carrier or a block list. A generated value can collide with an assigned identifier, and the local label is not an authoritative device classification. Use the methodology to record the snapshot and limitations with your test data.

FAQ

How many digits are in an IMEI?

The form normally shown to a user has 15 decimal digits: an 8-digit TAC, a 6-digit serial portion and a 1-digit Luhn check digit. IMEISV is a separate 16-digit format with a 2-digit software version number instead of that check digit.

Does every phone have an IMEI?

Cellular-capable equipment can have an IMEI; Wi-Fi-only devices do not need one. A dual-SIM or multi-profile device can expose more than one IMEI. Check the manufacturer's documentation for the model.

Does a valid Luhn check prove that an IMEI is real?

No. Luhn detects some entry errors. It does not query assignment records and cannot prove that a device exists, belongs to the stated model, is unlocked or is absent from a block list.

Is IMEI the same as ICCID or IMSI?

No. IMEI identifies cellular equipment. ICCID identifies a SIM or eSIM profile, while IMSI identifies a mobile subscription in the operator's systems.

Where can I find my device's IMEI?

Check the device settings first. Many phones also display it after dialing *#06#. Apple and Samsung document additional model-dependent locations such as account pages, packaging, SIM trays or the device body.

Can Random IMEI verify ownership or blacklist status?

No. Random IMEI generates test fixtures and validates structure. Use your carrier or an official or industry-backed status service for a real device.