title: Calculate Time difference using UNIX time stamp in PHP
body: <p>I have 2 unix time, one is todays date and other is expiration time.</p>
  
  <ul>
  <li>Todays Time: 1377173245 (2013-08-22 12:07:25)</li>
  <li>Expiration Time: 1406303166 (2014-07-25 15:46:06)</li>
  </ul>
  
  <p>What I want to achieve is calculate remaining time to expire the listing. In current case, it should show, <code>11 months -- hours -- minutes -- seconds</code> I didn't find any good solution to calculate the difference. I doubt is it possible to calculate time difference using UNIX time system?</p>
  
  <p>Thank you :-)</p>