title: PHP - add 1 day to date format mm-dd-yyyy
body: <pre><code>&lt;?php
      $date = "04-15-2013";
      $date = strtotime($date);
      $date = strtotime("+1 day", $date);
      echo date('m-d-Y', $date);
  ?&gt;
  </code></pre>
  
  <p>This is driving me crazy and seems so simple. I'm pretty new to PHP, but I can't figure this out. The echo returns <code>01-01-1970</code>.</p>
  
  <p>The $date will be coming from a <code>POST</code> in the format <code>m-d-Y</code>, I need to add one day and have it as a new variable to be used later.</p>
  
  <p>Do I have to convert $date to <code>Y-m-d</code>, add 1 day, then convert back to <code>m-d-Y</code>?
  Would I be better off learning how to use <code>DateTime</code>?</p>