Adding 1 hour to time variable

Worked for me..

$timestamp = strtotime('10:09') + 60*60;

$time = date('H:i', $timestamp);

echo $time;//11:09

Explanation:

strtotime('10:09') creates a numerical timestamp in seconds, something like 1510450372. Simply add or remove the amount of seconds you need and use date() to convert it back into a human readable format.

$timestamp = strtotime('10:09') + 60*60; // 10:09 + 1 hour
$timestamp = strtotime('10:09') + 60*60*2; // 10:09 + 2 hours
$timestamp = strtotime('10:09') - 60*60; // 10:09 - 1 hour

time() also creates a numerical timestamp but for right now. You can use it in the same way.

$timestamp = time() + 60*60; // now + 1 hour