Create Variable in PHP Equal to Current Time Minus One Hour

If you're looking for how to display the time in a human readable format, these examples will help:

$livetime = date('H:i:s', time() - 3600); // 16:00:00
$livetime = date('g:iA ', time() - 3600); // 4:00PM

Another way - without all the math and, in my opinion, reads better.

$hour_ago = strtotime('-1 hour');