Here is the code and issue with calculation using your functions

[akathuria2015]

          Here is the code and issue with calculation using your functions

Below is the code to add the year month day to Ethiopian date of 07/03/2016 in the format of dd/mm/yyyy
$et = '07/03/2016'; // Ethiopic date string in dd/mm/yyyy format
[$day, $month, $year] = explode('/', $et); // split it by the delimiter

    $date = Andegna\DateTimeFactory::of($year, $month, $day);

    $sentencedate =$date->add(new \DateInterval('P1Y3M15D'));

    //$sentencedate = $date->modify('+15 days +3 months +1 year');

    //$sentencedate = $sentencedate->modify('-1 day');
    dd($sentencedate); 

output of this code is 25/06/2017 which is wrong as it does not take into account the Ethiopian months are 30 days for 12 months and the 13th month is 5 or 6 days depending on the leap year. if you take this into account the correct 17/06/2017. how can I solve this using PHP. This date of 07/03/2016 can be any date entered by the user in Ethiopian format

Originally posted by @akathuria2015 in #44 (comment)