IMEI vs Serial Number: What’s the Difference?

Phones have two key identifiers, and using the wrong one leads to a failed or empty lookup. Here is the difference.

What the IMEI is for

The IMEI (15 digits) is the device's network identity. It is used for blacklist, carrier and SIM-lock checks — anything tied to the cellular network. Run a Full IMEI Check or the GSMA Blacklist Check with it.

What the serial number is for

The serial number is the manufacturing identity used by the maker for warranty and service. Apple warranty lookups need the serial, not the IMEI — use the Apple Warranty by Serial Check.

When to use which

• Buying safety (stolen/locked): use the IMEI.
• Warranty / service coverage: use the serial number.
• Full picture: use both via the Full IMEI Check and serial lookup.

Bottom line

IMEI for network checks, serial for warranty checks. Keep both handy before you buy a used device.