Código PHP:
<?php
$dateFrom = "25-03-2005 14:20:00";
$dateTo = date("d-m-Y H:i:s", strtotime('now'));
$diffd = getDateDifference($dateFrom, $dateTo, 'd');
$diffh = getDateDifference($dateFrom, $dateTo, 'h');
$diffm = getDateDifference($dateFrom, $dateTo, 'm');
$diffs = getDateDifference($dateFrom, $dateTo, 's');
$diffa = getDateDifference($dateFrom, $dateTo, 'a');
echo 'Calculating difference between ' . $dateFrom . ' and ' . $dateTo . ' <br /><br />';
echo $diffd . ' days.<br />';
echo $diffh . ' hours.<br />';
echo $diffm . ' minutes.<br />';
echo $diffs . ' seconds.<br />';
echo '<br />In other words, the difference is ' . $diffa['days'] . ' days, ' . $diffa['hours'] . ' hours, ' . $diffa['minutes'] . ' minutes and ' . $diffa['seconds'] . ' seconds.<br>';
?>
Here's the code:
<?php
/**
* Calculates the difference for two given dates, and returns the result
* in specified unit.
*
* @param string Initial date (format: [dd-mm-YYYY hh:mm:ss], hh is in 24hrs format)
* @param string Last date (format: [dd-mm-YYYY hh:mm:ss], hh is in 24hrs format)
* @param char 'd' to obtain results as days, 'h' for hours, 'm' for minutes, 's' for seconds, and 'a' to get an indexed array of days, hours, minutes, and seconds
*
* @return mixed The result in the unit specified (float for all cases, except when unit='a', in which case an indexed array), or null if it could not be obtained
*/
function getDateDifference($dateFrom, $dateTo, $unit = 'd')
{
$difference = null;
$dateFromElements = split(' ', $dateFrom);
$dateToElements = split(' ', $dateTo);
$dateFromDateElements = split('-', $dateFromElements[0]);
$dateFromTimeElements = split(':', $dateFromElements[1]);
$dateToDateElements = split('-', $dateToElements[0]);
$dateToTimeElements = split(':', $dateToElements[1]);
// Get unix timestamp for both dates
$date1 = mktime($dateFromTimeElements[0], $dateFromTimeElements[1], $dateFromTimeElements[2], $dateFromDateElements[1], $dateFromDateElements[0], $dateFromDateElements[2]);
$date2 = mktime($dateToTimeElements[0], $dateToTimeElements[1], $dateToTimeElements[2], $dateToDateElements[1], $dateToDateElements[0], $dateToDateElements[2]);
if( $date1 > $date2 )
{
return null;
}
$diff = $date2 - $date1;
$days = 0;
$hours = 0;
$minutes = 0;
$seconds = 0;
if ($diff % 86400 <= 0) // there are 86,400 seconds in a day
{
$days = $diff / 86400;
}
if($diff % 86400 > 0)
{
$rest = ($diff % 86400);
$days = ($diff - $rest) / 86400;
if( $rest % 3600 > 0 )
{
$rest1 = ($rest % 3600);
$hours = ($rest - $rest1) / 3600;
if( $rest1 % 60 > 0 )
{
$rest2 = ($rest1 % 60);
$minutes = ($rest1 - $rest2) / 60;
$seconds = $rest2;
}
else
{
$minutes = $rest1 / 60;
}
}
else
{
$hours = $rest / 3600;
}
}
switch($unit)
{
case 'd':
case 'D':
$partialDays = 0;
$partialDays += ($seconds / 86400);
$partialDays += ($minutes / 1440);
$partialDays += ($hours / 24);
$difference = $days + $partialDays;
break;
case 'h':
case 'H':
$partialHours = 0;
$partialHours += ($seconds / 3600);
$partialHours += ($minutes / 60);
$difference = $hours + ($days * 24) + $partialHours;
break;
case 'm':
case 'M':
$partialMinutes = 0;
$partialMinutes += ($seconds / 60);
$difference = $minutes + ($days * 1440) + ($hours * 60) + $partialMinutes;
break;
case 's':
case 'S':
$difference = $seconds + ($days * 86400) + ($hours * 3600) + ($minutes * 60);
break;
case 'a':
case 'A':
$difference = array (
"days" => $days,
"hours" => $hours,
"minutes" => $minutes,
"seconds" => $seconds
);
break;
}
return $difference;
}
?>
http://www.forosdelweb.com/f18/comparar-dos-fechas-con-php-364636/
usemos el buscador ... !!! saludos