if($_POST['calc']) {

   $data = $_POST['calc'];

   $percent = 10;
   $start_summ = (int)str_replace(" ","",$data['contribution']);

   if ($data['radio'] == 'yes') {
      $summ_add = (int)str_replace(" ","",$data['adjunction']);
   } else {
      $summ_add = 0;
   }

   $date = new DateTime($data['date']);
   $day = (int)$date->format('d');
   $month = (int)$date->format('m');
   $year = (int)$date->format('Y');

   $summ = 0;

   for ($i = 1; $i <= ((int)($data['years']))*12; $i++) {

      if ($i == 1) {
         $days_in_month = (int)$date->format('t')-$day;
         $summ_add = 0;
      } else {
         $date->modify('+ 1 month');
         $day = (int)$date->format('d');
         $month = (int)$date->format('m');
         $year = (int)$date->format('Y');
         $days_in_month = (int)$date->format('t');
      }

      if (($year % 4) == 0) {
         $days = 366;
      } else {
         $days = 365;
      }
      var_dump($days_in_month);

      $summ += ($start_summ + ($start_summ + $summ_add))*($days_in_month*($percent/$days));

   }



   echo $summ;

   //echo number_format($summ, 2, ',', ' ');

   exit;

}