Calculating Hour Difference Between Dates in PHP

When comparing two dates represented as "Y-m-d H:i:s", determining the hour difference between them is a common requirement. Here's how to achieve this in PHP:

Converting to Timestamps

The first step is to convert both dates to Unix timestamps, which represent the number of seconds since the Unix epoch (January 1, 1970 at 00:00:00 UTC). This can be done using the strtotime() function:

$timestamp1 = strtotime($time1);
$timestamp2 = strtotime($time2);

Calculating Hour Difference

Once we have the timestamps, we can subtract them to get the difference in seconds:

$seconds_difference = $timestamp1 - $timestamp2;

To convert this to hours, we divide by 3600, since there are 3600 seconds in an hour:

$hour_difference = round($seconds_difference / 3600, 1);

The round() function is used to avoid having a lot of decimal places.

Example Usage

Let's say we have two dates:

$time1 = "2023-05-25 15:30:15";
$time2 = "2023-05-26 09:45:30";

Using the code above:

$timestamp1 = strtotime($time1);
$timestamp2 = strtotime($time2);

$seconds_difference = $timestamp1 - $timestamp2;
$hour_difference = round($seconds_difference / 3600, 1);

echo "Hour difference: $hour_difference hours";

This would output:

Hour difference: 17.5 hours