Adding minutes to date time in PHP

$newtimestamp = strtotime('2011-11-17 05:05 + 16 minute');
echo date('Y-m-d H:i:s', $newtimestamp);

result is

2011-11-17 05:21:00

Live demo is here

If you are no familiar with strtotime yet, you better head to php.net to discover it's great power :-)

$minutes_to_add = 5;

$time = new DateTime('2011-11-17 05:05');
$time->add(new DateInterval('PT' . $minutes_to_add . 'M'));

$stamp = $time->format('Y-m-d H:i');

The ISO 8601 standard for duration is a string in the form of P{y}Y{m1}M{d}DT{h}H{m2}M{s}S where the {*} parts are replaced by a number value indicating how long the duration is.

For example, P1Y2DT5S means 1 year, 2 days, and 5 seconds.

In the example above, we are providing PT5M (or 5 minutes) to the DateInterval constructor.

PHP's DateTime class has a useful modify method which takes in easy-to-understand text.

$dateTime = new DateTime('2011-11-17 05:05');
$dateTime->modify('+5 minutes');

You could also use string interpolation or concatenation to parameterize it:

$dateTime = new DateTime('2011-11-17 05:05');
$minutesToAdd = 5;
$dateTime->modify("+{$minutesToAdd} minutes");