How To Find An Email Address By Facebook ID

Every Facebook user has an email address in the form of Facebook_ID@facebook.com. When you email that address from any email client, the message normally routes to the user's Facebook message inbox. However, if you know a friend or business contact's Facebook ID and want to locate her non-Facebook email address, you can use the ID to visit the associated profile. The contact information only appears if it is public or the user has made it viewable by you.
 Step 1

Log in to Facebook and click inside the address bar in your Web browser.
Step 2

Delete all characters that appear to the right of the forward slash following "facebook.com."

Step 3

Type the Facebook ID of the user whose email address you want to find and press "Enter" on your keyboard. This navigates your browser to the user's Facebook profile.
Step 4

Click "About" in the user's profile to view all of the available information about that user.
Step 5

Scroll down the page until you see the "Contact Info" section. If an "Email" field appears there, all of the user's email addresses visible to you are adjacent to it.