IMEI vs Serial Number: Which One Do You Need?
Two different identifiers, two different jobs. Here is when each matters.
Every phone carries at least two identifiers, and confusing them leads to checks that return nothing. The IMEI is a globally standardized 15-digit cellular identity used by networks everywhere. The serial number is the manufacturer's own internal code, used mainly for warranty and support.
For buying a used phone, the IMEI is almost always what you want. It unlocks lock status, blacklist history and activation state — the invisible risks. Keep the serial number handy too, since it can corroborate the device identity and warranty, but lead with the IMEI.
The distinction has real consequences. Carrier-lock and blacklist databases are keyed to the IMEI, because those systems live at the network level. Ask them about a serial number and they have nothing to say. Warranty systems, by contrast, often accept either — Apple, for instance, resolves both to the same device record.
One practical tip: verify that the IMEI, the serial and the physical device all agree. On an iPhone, Settings shows both numbers; *#06# shows the IMEI. If a report, the box and the phone disagree, you may be looking at a cloned or Frankenstein device.
Check any IMEI free
See device, blacklist and lock status in seconds — no signup.
Check an IMEI free →Common questions
Which is better for checking a used phone, IMEI or serial?
The IMEI. Lock, blacklist and activation databases are keyed to it. The serial is mainly for warranty and support.
Can I get lock status from a serial number?
Generally no — network lock and blacklist systems use the IMEI. Use the IMEI for those checks.
Where do I find the serial number?
In Settings → General → About on iPhone, or Settings → About phone on Android, and often on the original box.
Should the IMEI and serial match a single device?
They identify the same phone through different systems. If a report ties them to different models, treat that as a red flag.