Calculate the difference between date/times in PHP

Question

I have a Date object ( from Pear) and want to subtract another Date object to get the time difference in seconds.

I have tried a few things but the first just gave

Answer 1

I don't think you should be passing the entire Date object to strtotime. Use one of these instead;

$start = strtotime($now->getDate());

or

$start = $now->getTime();

Answer 2

Are you sure that the conversion of Pear Date object -> string -> timestamp will work reliably? That is what is being done here:

$start = strtotime($now);

As an alternative you could get the timestamp like this according to the documentation

$start = $now->getTime();

Answer 3

Still gave somewhat wrong values but considering I have an old version of PEAR Date around, maybe it works for you or gives you an hint on how to fix :)

<pre>
<?php
  require "Date.php";

  $now = new Date();
  $target = new Date("2009-07-02 15:00:00");

  //Bring target to current timezone to compare. (From Hawaii to GMT)
  $target->setTZByID("US/Hawaii");
  $target->convertTZByID("America/Sao_Paulo");

  $diff = new Date_Span($target,$now);

  echo "Now (localtime): {$now->format("%Y-%m-%d %H:%M:%S")} \n\n";
  echo "Target (localtime): {$target->format("%Y-%m-%d %H:%M:%S")} \n\n";
  echo $diff->format("Diff: %g seconds => %C");
?>
</pre>

Answer 4

Maybe some folks wanna have the time difference the facebook way. It tells you "one minute ago", or "2 days ago", etc... Here is my code:

function getTimeDifferenceToNowString($timeToCompare) {

        // get current time
        $currentTime = new Date();
        $currentTimeInSeconds = strtotime($currentTime);
        $timeToCompareInSeconds = strtotime($timeToCompare);

        // get delta between $time and $currentTime
        $delta = $currentTimeInSeconds - $timeToCompareInSeconds;

        // if delta is more than 7 days print the date
        if ($delta > 60 * 60 * 24 *7 ) {
            return $timeToCompare;
        }   

        // if delta is more than 24 hours print in days
        else if ($delta > 60 * 60 *24) {
            $days = $delta / (60*60 *24);
            return $days . " days ago";
        }

        // if delta is more than 60 minutes, print in hours
        else if ($delta > 60 * 60){
            $hours = $delta / (60*60);
            return $hours . " hours ago";
        }

        // if delta is more than 60 seconds print in minutes
        else if ($delta > 60) {
            $minutes = $delta / 60;
            return $minutes . " minutes ago";
        }

        // actually for now: if it is less or equal to 60 seconds, just say it is a minute
        return "one minute ago";

    }

Answer 5

To do it without pear, to find the seconds 'till 17:00 you can do:

$current_time = mktime (); 
$target_time = strtotime (date ('Y-m-d'. ' 17:00:00')); 
$timediff = $target_time - $current_time;

Not tested it, but it should do what you need.