Use the dialler
On most phones, open the phone app and dial *#06#. The IMEI appears on screen. Do not place a call or share a screenshot publicly.
On iPhone
Open Settings → General → About and scroll to IMEI. For a dual-SIM model, there may be more than one IMEI.
On Android
Open Settings → About phone (the wording varies by manufacturer) and look for IMEI or IMEI information.
Keep it private
An IMEI uniquely identifies a handset. Avoid posting it publicly. MobileUnlock's current checker validates digits in your browser tab only and does not query a device database.
Open the IMEI format checker