How to add days, weeks, months to date in PHP

Add days, weeks, months to date.

$date = date(Y-m-d);
$date = strtotime(date(Y-m-d, strtotime($date)) . ' +1 day');$date = strtotime(date(Y-m-d, strtotime($date)) . ' +1 week');$date = strtotime(date(Y-m-d, strtotime($date)) . ' +2 week');$date = strtotime(date(Y-m-d, strtotime($date)) . ' +1 month');$date = strtotime(date(Y-m-d, strtotime($date)) . ' +30 days');echo date(Y-m-d, $date);