How to compare two dates using PHP

• First we need to convert the two dates to UNIX Timestamps using the PHP function strtotime
• Then we can compare the two dates in anyway we wish, in the example below I’m checking that the first date is older than the second date 

  $date1 = '1999-10-11';
  $date2 = '2010-10-11';
   
  $firstDate = strtotime($date1);
  $secondDate = strtotime($date2);
   
  if($firstDate < $secondDate){
       echo 'First date is older';
  }else{
       echo 'Second date is older';
  }