How an IMEI works
An IMEI is 15 digits in three parts: which model it is, which unit it is, and a check digit that catches typos.
The three parts
- TAC
- 35693803 · digits 1–8: the device model the IMEI was allocated to
- serial
- 564380 · digits 9–14: this individual unit
- check digit
- 9 · digit 15: calculated from the other 14
Example IMEI 356938035643809, the standard worked example used in documentation.
The check digit, worked through
The check digit uses the Luhn formula. Take the first 14 digits; double every second digit (the 2nd, 4th, 6th…); if doubling gives a two-digit number, add its digits (subtract 9); add everything up; the check digit is whatever brings the total to the next multiple of 10.
| Position | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Digit | 3 | 5 | 6 | 9 | 3 | 8 | 0 | 3 | 5 | 6 | 4 | 3 | 8 | 0 |
| Counted as | 3 | 10→1 | 6 | 18→9 | 3 | 16→7 | 0 | 6 | 5 | 12→3 | 4 | 6 | 8 | 0 |
Total: 61. The next multiple of 10 is 70, so the check digit is 9 and the full IMEI is 356938035643809.
A wrong check digit means a typo or a made-up number. A right one only means the number is well-formed, not that the device exists or is legitimate. Our free validator does this check for you.
Questions
What is a TAC?
The Type Allocation Code is the first 8 digits of an IMEI. It identifies the device model (and often the market variant) the IMEI was allocated to; the remaining digits identify the individual unit.
Is an IMEI the same as a serial number?
No. The IMEI identifies the device on mobile networks and is defined by a global standard; a manufacturer's serial number is its own internal identifier and has a different format.
Can an IMEI tell you if a phone is stolen?
Not on its own. Whether a phone is reported lost or stolen is held by network operators and blacklist services. Decoding the IMEI tells you what the device is, not its status, and our decoder does not check blacklists.
Why does my phone have two IMEIs?
Dual-SIM phones have one IMEI per SIM slot (including eSIM). Both usually share the same TAC, so they decode to the same model.
What is an IMEISV?
A 16-digit variant: the same 14 identifying digits followed by a 2-digit software version number instead of the check digit.
How do I find my IMEI?
Dial *#06# on most phones, or look in the device settings under About. It is also printed on the box and usually the SIM tray.
Decode an IMEI
Get the brand and model behind any IMEI from our own database: IMEI decoder API.
Published by fourzerotwo · last reviewed 11 October 2026