Breaking down a 15-digit IMEI
An IMEI is actually three numbers stitched together:
| Digits | Section | What it means |
|---|---|---|
| 1–8 | TAC (Type Allocation Code) | Identifies the manufacturer and model. |
| 9–14 | Serial | Unique to this device within that model. |
| 15 | Check digit | Luhn checksum to catch typos. |
What is the TAC?
The Type Allocation Code is assigned by the GSMA to manufacturers when they certify a device. Every iPhone 15 Pro, for example, shares the same set of TACs — different production batches and regional variants may each get a different TAC, but they all decode to the same brand and model.
Why the TAC is enough for most lookups
When you "check an IMEI" for the model name, the lookup tool is usually just consulting a TAC-to-model database. The remaining 7 digits are not needed.
The remaining digits are needed for blacklist checks, carrier checks and warranty checks — those tie back to a specific device.
The check digit, briefly
The 15th digit is a Luhn checksum computed over the first 14. It catches single-digit typos but nothing more clever — so a Luhn-valid IMEI is not necessarily a real one.
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