Gera Tools

IMEI Number Validator

Validate mobile device IMEI numbers via Luhn algorithm

Validate a 15-digit mobile IMEI with the Luhn check-digit algorithm, see the TAC and serial breakdown, and get the correct check digit if it fails. Runs entirely in your browser — nothing is uploaded. It runs free in your browser on Gera Tools, with nothing uploaded.

Last updated Source: Gera Tools

How is an IMEI validated?

The 15th digit is a Luhn check digit over the first 14. Doubling every second digit from the right, subtracting 9 where the result exceeds 9, and summing all digits including the check digit must produce a total divisible by 10.

An IMEI (International Mobile Equipment Identity) is the 15-digit number that uniquely identifies a mobile phone or cellular modem on a global network. Every phone that connects to a cellular network has one, and carriers use it to track, register, and blacklist devices. The final digit is a Luhn check digit — the same algorithm used on credit card numbers — which lets you catch typos before submitting the number anywhere.

IMEI structure

A standard IMEI has three fields across 15 digits:

[ TAC: 8 digits ][ Serial: 6 digits ][ Check: 1 digit ]
  49015420         323751              8
  • TAC (Type Allocation Code): First 8 digits. Identifies the device model and manufacturer. Allocated by the GSMA. All phones of the same model share the same TAC.
  • Serial number: Digits 9–14. A unique sequence within a given TAC, assigned by the manufacturer. No two phones with the same TAC should share the same serial.
  • Check digit: Digit 15. Computed by the Luhn algorithm over the first 14 digits. Catches single-digit transcription errors.

How the Luhn check works

  1. Starting from the rightmost digit (the check digit), double every second digit moving left.
  2. If doubling produces a value above 9, subtract 9 from it.
  3. Sum all the resulting digits.
  4. If the total is divisible by 10, the IMEI is structurally valid.

For example, working through 490154203237518:

  • Position 14 (second from right): 1 → double → 2
  • Position 13 (fifth from right): 5 → double → 10 → 10 − 9 = 1
  • … and so on across all 15 digits.
  • Final sum: divisible by 10 → valid.

If you mistype a single digit, the Luhn sum almost always fails to end in 0, and the validator rejects it. The tool also shows the correct check digit for the first 14 digits you entered, so you can identify where the error is.

Where to find your IMEI

  • Dial *#06# on any cellular phone — the IMEI appears on screen.
  • Settings: on iPhone, go to Settings → General → About; on Android, look in Settings → About phone → IMEI.
  • SIM tray or box: many phones print the IMEI on the device itself and on the retail packaging.
  • Phones with two SIM slots have two IMEIs — IMEI1 and IMEI2.

What a valid IMEI confirms and what it does not

A passing Luhn check only means the number is structurally well-formed. It does not tell you whether the device is stolen, blacklisted, or even real. Checking actual device status requires a carrier lookup or a GSMA IMEI database query, which this tool does not perform.

All processing is local to your browser — your IMEI is never transmitted anywhere.