background-position: 50% center;
<!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> <title>background-position</title> <style type='text/css'> div { width: 100px; height: 100px; border: 1px solid rgb(128, 128, 128); margin: 4px; float: left; background-image: url('http://java2s.com/style/logo.png'); background-repeat: no-repeat; font: 12px sans-serif; } div#percentage-keyword {background-position: 50% center;} </style> </head> <body> <div id='percentage-keyword'>50%, center</div> </body> </html>