adding two time values of similar formats using php

Use this function...

 function sum_the_time($time1, $time2) {
      $times = array($time1, $time2);
      $seconds = 0;
      foreach ($times as $time)
      {
        list($hour,$minute,$second) = explode(':', $time);
        $seconds += $hour*3600;
        $seconds += $minute*60;
        $seconds += $second;
      }
      $hours = floor($seconds/3600);
      $seconds -= $hours*3600;
      $minutes  = floor($seconds/60);
      $seconds -= $minutes*60;
      if($seconds < 9)
      {
      $seconds = "0".$seconds;
      }
      if($minutes < 9)
      {
      $minutes = "0".$minutes;
      }
        if($hours < 9)
      {
      $hours = "0".$hours;
      }
      return "{$hours}:{$minutes}:{$seconds}";
    }

strtotime function takes full-date as an argument and valid format are as following: http://www.php.net/manual/en/datetime.formats.php

You can see that in online PHP manual for the function at http://php.net/manual/en/function.strtotime.php

If you're build those time strings from a database before, you'd probably want to rebuild them to something like this:

$time = "00:06:58";
$time2 = "40 minutes";

$timestamp = strtotime($time." +".$time2);
$endTime = date("d.m.Y H:i:s", $timestamp);

Easiest way to add two times using php is :

1) Convert time from H:i:s (e.g. 08:15:40) format to seconds.
2) do the same for second time value ref:step 1
3) add converted values and store it php variable
4) Now convert total (which is in seconds) to H:i:s
and it works for me.

PHP Script:

$str_time ="08:04:40";

$str_time = preg_replace("/^([\d]{1,2})\:([\d]{2})$/", "00:$1:$2", $str_time);

sscanf($str_time, "%d:%d:%d", $hours, $minutes, $seconds);

$hrs_old_seconds = $hours * 3600 + $minutes * 60 + $seconds;

$str_time ="02:10:22";

$str_time = preg_replace("/^([\d]{1,2})\:([\d]{2})$/", "00:$1:$2", $str_time);

sscanf($str_time, "%d:%d:%d", $hours, $minutes, $seconds);

$hrs_toadd_seconds = $hours * 3600 + $minutes * 60 + $seconds;

$hrs_old_int1 = $hrs_old_seconds + $hrs_toadd_seconds;

echo $Total=gmdate("H:i:s", $hrs_old_int1);

Result= :10:15:02

Anudeep's solution was great for my use case, but I needed to be able to add negative times as well. Here's a slightly edited version of his code to take and return negative time strings ("-01:01:01" for example):

public static function sum_the_times($time1, $time2)
{
    $times = array($time1, $time2);
    $seconds = 0;
    $negative = false;
    foreach ($times as $time) {
        list($hour,$minute,$second) = explode(':', $time);
        if(substr($hour,0,1) == '-'){
            $seconds -= substr($hour,1)*3600;
            $seconds -= $minute*60;
            $seconds -= $second;
        } else {
            $seconds += $hour*3600;
            $seconds += $minute*60;
            $seconds += $second;
        }
    }
    if (substr($seconds, 0, 1) == '-') {
        $negative = true;
        $seconds = ($seconds * -1);
    }
    $hours = floor($seconds/3600);
    $seconds -= $hours*3600;
    $minutes  = floor($seconds/60);
    $seconds -= $minutes*60;
    if ($seconds < 9) {
        $seconds = "0".$seconds;
    }
    if ($minutes < 9) {
        $minutes = "0".$minutes;
    }
    if ($hours < 9) {
        $hours = "0".$hours;
    }
    return ($negative ? "-" : "")."{$hours}:{$minutes}:{$seconds}";
}

You can try this

$time = "04:00:00";
$time2 = "03:30:00";

$result = date("H:i:s",strtotime($time)+strtotime($time2));
echo $result;

It gives output 07:30:00 but it does not work sometime in different version of operating system. If you want to get sum of time then you can use this code

<?php
   function CalculateTime($time1, $time2) {
      $time1 = date('H:i:s',strtotime($time1));
      $time2 = date('H:i:s',strtotime($time2));
      $times = array($time1, $time2);
      $seconds = 0;
      foreach ($times as $time)
      {
        list($hour,$minute,$second) = explode(':', $time);
        $seconds += $hour*3600;
        $seconds += $minute*60;
        $seconds += $second;
      }
      $hours = floor($seconds/3600);
      $seconds -= $hours*3600;
      $minutes  = floor($seconds/60);
      $seconds -= $minutes*60;
      if($seconds < 9)
      {
      $seconds = "0".$seconds;
      }
      if($minutes < 9)
      {
      $minutes = "0".$minutes;
      }
        if($hours < 9)
      {
      $hours = "0".$hours;
      }
      return "{$hours}:{$minutes}:{$seconds}";
    }

    $time1= '23:32:05';
    $time2 = '01:29';
    echo CalculateTime($time1,$time2);

?>

In the second code, you can send time in hour:minutes or hours:minutes:seconds. This code accept both format because it convert time automatically

Here's a version that will cater for over 24 hours and doesn't use strtotime:

$time0 = "24:01:02";
$time1 = "01:02:03";
$matches0 = explode(':',$time0); // split up the string
$matches1 = explode(':',$time1);
$sec0 = $matches0[0]*60*60+$matches0[1]*60+$matches0[2];
$sec1 = $sec0+ $matches1[0]*3600+$matches1[1]*60+$matches1[2]; // get total seconds
$h = intval(($sec1)/3600);
$m = intval(($sec1-$h*3600)/60);
$s = $sec1-$h*3600-$m*60;
echo $str = str_pad($h, 2, '0', STR_PAD_LEFT).':'.str_pad($m, 2, '0', STR_PAD_LEFT).':'.str_pad($s, 2, '0', STR_PAD_LEFT);