<?php
$january = new DateTime('2010-01-01');
$february = new DateTime('2010-02-01');
$interval = $february->diff($january);
// %a will output the total number of days.
// While %d will only output the number of days not already covered by the
// month.
if ($interval->format('%a')/30 > 1) {
echo $interval->format('%m month, %d days');
} else {
echo $interval->format('%a total days')."\n";
}
?>