I think we need to write a custom function for that

Hello Vishal,

In OOTB Pega does not any function to return the no. of days for a given month. for that, you have implement custom logic.

Like:

From given input date, extract a day, month and year then pass to below calender.set to get the no. of days.

Calendar calendar = java.util.Calendar.getInstance();
  calendar.set(year, month, date);
  int days = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);

Regards,

Praveen