What is a TAC?

Where the TAC sits

In the 15 digits of an IMEI, the TAC is the first eight:

49015420 323751 8 — TAC, then serial, then check digit.

Because the TAC is fixed per model, two phones of the same model bought in the same market share it. Their serials differ; their TACs do not.

Who assigns them

The GSMA, the industry body for mobile operators, allocates TACs to manufacturers. A manufacturer applies for a code before shipping a model, which is why a genuinely new device shows up in TAC databases around its release rather than years later.

One model can hold several TACs — different storage tiers, regional variants, or carrier-specific versions are often allocated separately. This is why a lookup sometimes returns a model name that is slightly more or less specific than you expected.

Why it matters practically

The TAC is the reason a free IMEI lookup works at all. Identifying a device does not require querying a network or a manufacturer — it requires a table mapping eight digits to a make and model. That table is public, it can be held locally, and the lookup is instant.

It also means you only need the first eight digits to identify a model. If a seller sends you a partial IMEI, or you can only read part of a label, eight digits is enough for make and model — though not enough to validate the checksum, which needs all fifteen.

The limits of TAC data

TAC databases are compiled, and compilations go stale. A very recently released handset may not be listed yet, and a lookup will honestly say it does not know rather than guess. That is a data-freshness limit, not a sign the IMEI is fake.

And identification is all it is. The TAC tells you what kind of device a number belongs to. It says nothing about that particular unit's history — see what an IMEI check cannot tell you.