function timeDiff($time, $opt = array()) {
// The default values
$defOptions = array(
‘to’ => 0,
‘parts’ => 1,
‘precision’ => ’second’,
‘distance’ => TRUE,
’separator’ => ‘, ‘
);
$opt = array_merge($defOptions, $opt);
// Default to current time if no to point is given
(!$opt['to']) && ($opt['to'] = time());
// Init an empty string
$str = ”;
// To or From computation
$diff = ($opt['to'] > $time) ? $opt['to']-$time : $time-$opt['to'];
// An array of label => periods of seconds;
$periods = array(
‘decade’ => 315569260,
‘year’ => 31556926,
‘month’ => 2629744,
‘week’ => 604800,
‘day’ => 86400,
‘hour’ => 3600,
‘minute’ => 60,
’second’ => 1
);
// Round to precision
if ($opt['precision'] != ’second’)
$diff = round(($diff/$periods[$opt['precision']])) * $periods[$opt['precision']];
// Report the value is ‘less than 1 ‘ precision period away
(0 == $diff) && ($str = ‘less than 1 ‘.$opt['precision']);
// Loop over each period
foreach ($periods as $label => $value) {
// Stitch together the time difference string
(($x=floor($diff/$value))&&$opt['parts']–) && $str.=($str?$opt['separator']:”).($x.’ ‘.$label.($x>1?’s’:”));
// Stop processing if no more parts are going to be reported.
if ($opt['parts'] == 0 || $label == $opt['precision']) break;
// Get ready for the next pass
$diff -= $x*$value;
}
$opt['distance'] && $str.=($str&&$opt['to']>$time)?’ ago’:”;
return $str;
}

http://www.isthisablog.com/2009/06/19/php-elapsed-time-function/comment-page-1/#comment-2962#ixzz0IstcSgQ1&D