Time calculation in php (add 10 hours)?

strtotime() gives you a number back that represents a time in seconds. To increment it, add the corresponding number of seconds you want to add. 10 hours = 60*60*10 = 36000, so...

$date = date('h:i:s A', strtotime($today)+36000); // $today is today date

Edit: I had assumed you had a string time in $today - if you're just using the current time, even simpler:

$date = date('h:i:s A', time()+36000); // time() returns a time in seconds already

$date = date('h:i:s A', strtotime($today . ' + 10 hours'));

(untested)

$tz = new DateTimeZone('Europe/London');
$date = new DateTime($today, $tz);
$date->modify('+10 hours');
// use $date->format() to outputs the result.

see DateTime Class (PHP 5 >= 5.2.0)