How to Subtract Minutes

To subtract 15 minutes from the current time, you can use strtotime():

$newTime = strtotime('-15 minutes');
echo date('Y-m-d H:i:s', $newTime);

you can try this as well,

$dateTimeMinutesAgo = new DateTime("15 minutes ago");
$dateTimeMinutesAgo = $dateTimeMinutesAgo->format("Y-m-d H:i:s");

Change the date into a timestamp (in seconds) then minus 15 minutes (in seconds) and then convert back to a date:

$date = date("Y-m-d H:i:s");
$time = strtotime($date);
$time = $time - (15 * 60);
$date = date("Y-m-d H:i:s", $time);

You can use DateInterval

$date = new DateTime();
$interval = new DateInterval("PT15M");
$interval->invert = 1;
$date->add($interval);
echo $date->format("c") . "\n";

Related