Every phone that has ever connected to a mobile network carries an IMEI — an International Mobile Equipment Identity. It identifies the handset itself, not the SIM card and not the person holding it. Dial *#06# on any phone and it appears; on iPhone it is also in Settings › General › About, and on most Android handsets in Settings › About phone.
What the number is made of
The fifteen digits are not random. The first eight are the Type Allocation Code, which identifies the model — that is how a check can tell you a number belongs to an iPhone 15 Pro 256GB rather than something else, before anyone has taken the phone out of the box. The next six are the serial number of that particular handset within the model. The last digit is a checksum.
The checksum is a Luhn digit, the same arithmetic that validates card numbers. It exists to catch a mistyped or misread number, and it is the first thing any honest check does. A number that fails the checksum is not a phone that does not exist — it is almost always a digit typed wrong.
A free format check confirms the number is well formed. It cannot tell you anything about the phone itself: that needs a lookup against the databases networks and manufacturers keep.
What a lookup can return
| Check | What it answers | Why it matters |
|---|---|---|
| Model and specification | Which handset the number belongs to | The listing says one model; the IMEI says another |
| Blacklist status | Whether it is reported lost, stolen or unpaid | A blacklisted handset loses network service, often after the sale |
| Carrier and country | Which network sold it, and where | A lock is filed with that network and no other |
| SIM lock status | Whether it is tied to one network | Decides whether an unlock is needed at all |
| Warranty and age | Purchase date and remaining cover | A "sealed, new" phone with two years of warranty gone is not new |
| Activation lock | Whether an Apple account still holds it | A locked device cannot be set up by anyone else |
Not every check answers every question. Reports are sold per source, because the sources are separate: a blacklist database is not the same system as a manufacturer warranty record. That is why prices differ between reports on the same phone.
What an IMEI check cannot tell you
- Who owns the phone. No lookup returns a name, an address or a phone number — that data is not in these databases, and a service offering it is selling something it does not have.
- Where the phone is. Location is a network and account function, not an IMEI lookup.
- What is on the phone. Photos, messages and accounts are not reachable from the number.
- Whether the seller is honest. It tells you about the handset, which is often enough to catch the problem.
A blacklist result reflects what has been reported so far. A phone reported stolen the day after you buy it will have been clean when you checked, which is why the receipt and the seller matter as much as the report.
Reading a result without over-reading it
Two results are commonly misread. "Clean" means not currently reported — it is a statement about a database on the day you asked, not a guarantee about the future. And "SIM locked" is not a fault: most phones sold on contract are locked by design, and the lock is removed by the network that applied it.
Run the format check for nothing, or see what the paid reports cover.
See phone check services