Do you want to find out the last date of the month in PHP. Here is a simple way by providing the valid date. It then takes the month from the date provided and returns the result.
1] Example to find out last date from the Month of the date parsed
$date = '2016-05-05'; echo date('Y-m-t', strtotime($date)); //output: 2016-05-31
2] Example to find out total number of days from Month of the date parsed
$date = '2016-05-05'; echo date('t', strtotime($date)); //output: 31
You can also test with the following dates such as..
$date = 'February'; // Or $date = 'today'; //Or $date = "this month"; //..etc.