 <p>try adding a parser like this guy does in here: <a href="http://jsbin.com/enata/edit" rel="nofollow">http://jsbin.com/enata/edit</a></p> <p>here is an article too: <a href="http://www.terminally-incoherent.com/blog/2008/09/29/jquery-tablesorter-list-of-builtin-parserssorters/" rel="nofollow">http://www.terminally-incoherent.com/blog/2008/09/29/jquery-tablesorter-list-of-builtin-parserssorters/</a></p>