In an effort to consolidate some things I’ve posted on my site in a less organized manner, here is a reprint of a function I came up with a few years ago for expressing the difference between two UNIX timestamp values (such as returned from the time() and mktime() functions). The result is an array of years, months, weeks, days, hours, minutes, and seconds.
<?php
/**
* Get difference between timestamps broken down into years/months/weeks/etc.
* @return array
* @param int $t1 UNIX timestamp
* @param int $t2 UNIX timestamp
*/
function timeDiff($t1, $t2)
{
if($t1 > $t2)
{
$time1 = $t2;
$time2 = $t1;
}
else
{
$time1 = $t1;
$time2 = $t2;
}
$diff = array(
'years' => 0,
'months' => 0,
'weeks' => 0,
'days' => 0,
'hours' => 0,
'minutes' => 0,
'seconds' =>0
);
foreach(array('years','months','weeks','days','hours','minutes','seconds')
as $unit)
{
while(TRUE)
{
$next = strtotime("+1 $unit", $time1);
if($next < $time2)
{
$time1 = $next;
$diff[$unit]++;
}
else
{
break;
}
}
}
return($diff);
}
Here’s a sample usage:
<?php
$start = strtotime('2007-01-15 07:35:55');
$end = strtotime('2009-11-09 13:01:00');
$diff = timeDiff($start, $end);
$output = "The difference is:";
foreach($diff as $unit => $value)
{
echo " $value $unit,";
}
$output = trim($output, ',');
echo $output;
?>
It would output:
The difference is: 2 years, 9 months, 3 weeks, 4 days, 5 hours, 25 minutes, 4 seconds