total day of a month in php code example

Example 1: php days in month

// For given month
echo cal_days_in_month(CAL_GREGORIAN, 1, 2021);
// For current month
echo date('t');

Example 2: php last day of month

$a_date = "2009-11-23";
echo date("Y-m-t", strtotime($a_date));