Your device’s serial number is a unique code that the manufacturer gives the phone. No two serial numbers are the same. Should you need to find your phone’s, there are a few places you can look.
A serial number is usually a combination of letter and numbers. There’s no set length— the manufacturer determines that. The serial number will usually be denoted by an “S/N:” on the box, as you’ll see below. As with all things Android, the path to your serial number may have different routes, but this guide should give you a general idea of where to look.
Option One: On Your Device’s Retail Packaging
Often, the box your device came in will carry the serial number. It’s usually located on the outside of the box on a sticker that also contains several bar codes, your device’s IMEI number, etc. It’ll either be on the back or the side of the box.
Option Two: Under Your Device’s Battery
These days, most Android devices come with non-removable batteries. But if you have a device with a removable battery, you will often be able to find the serial number printed underneath.
Option Three: In Your Device’s System Settings
To find your device’s serial number in the software, go to Settings > System.
Then jump into About Phone > Status.
from How-To Geek http://bit.ly/2YtOe3t