Subtract time in PHP

Question

I have been looking for an answer for a few hours now, but I can't find one.

I'm writing a simple script. The user sets their work start and end time. So, for example, somebody is working from 8:00 to 16:00. How can I subtract this time to see how long the person has been working?

I was experimenting with strtotime(); but without success...

Solution 1

A bit nicer is the following:

$a = new DateTime('08:00');
$b = new DateTime('16:00');
$interval = $a->diff($b);

echo $interval->format("%H");

That will give you the difference in hours.

Solution 2

If you get valid date strings, you can use this:

$workingHours = (strtotime($end) - strtotime($start)) / 3600;

This will give you the hours a person has been working.

Solution 3

Another solution would be to go through the Unix-timestamp integer value difference (in seconds).

<?php
    $start = strtotime('10-09-2019 12:01:00');
      $end = strtotime('12-09-2019 13:16:00');

      $hours = intval(($end - $start)/3600);
      echo $hours.' hours'; //in hours

      //If you want it in minutes, you can divide the difference by 60 instead
      $mins = (int)(($end - $start) / 60);
      echo $mins.' minutues'.'<br>';
?>

This solution would be a better one if your original dates are stored in Unix-timestamp format.

Comments

[jm_toball]

You can divide by 60 instead of 3600 to get minutes and divide by 60 and round down (floor()) to get full hours and get the remainder of minutes%60 to get the minutes.

[mjspier]

date ( 'H:i' , $workingHours ). I would not recommend strtottime here as strtotime gives you back the unix timestamp of a date.

[Aditya M P]

I wonder if it can convert the entire interval into seconds? ->format('%S') just gave me the seconds part of the interval output, not the total calculated seconds elapsed.

[Jason Aller]

Welcome to Stack Overflow. When answering an eight year old question with existing answers it is useful to point out what new aspect of the question your answer addresses. Code only answers can almost always be improved by adding explanation including why and how the code solves the problem.