p border: 1px solid rgb(200, 200, 200);
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns='http://www.w3.org/1999/xhtml' xml:lang='en'> <head> <meta http-equiv='Content-Type' content='text/html; charset=UTF-8' /> <title>Em Measurement Comparison to Pixels</title> <style type='text/css'> body { font: 1em sans-serif; } p { background: rgb(234, 234, 234); border: 1px solid rgb(200, 200, 200); } p#em-measurement { width: 12em; padding: 1em; } p#px-measurement { width: 192px; padding: 16px; } </style> </head> <body> <p id='em-measurement'> This paragraph is 12 em wide, with a 1em padding. </p> <p id='px-measurement'> This paragraph is 192 pixels wide, with 16 pixels of padding. </p> </body> </html>