Bear in mind the screen is measured diagonally and that part of the screen is covered by the bezel.  
Hello, I received my new Latitude 3420 today but the  screen is closer to 12 3/4 inches rather than the advertised 14 inches. (screen is actually less than 12 3/4 inches which is the width of the computer.  Is this standard for the 3420 or did I get a lemon?  
Latitude 3420 Screen Size