SQL & PL/SQL

I am using this to convert date to excel datevalue, is there a simple way to do this?

select to_date('31/12/2013', 'dd/mm/yyyy') normal_date,
    (trunc(to_date('31/12/2013', 'dd/mm/yyyy')) + CASE
  WHEN trunc(sysdate) >= to_date('01/01/1900', 'dd/mm/yyyy') then
   1
  else
   0
    end) - (to_date('01-01-1900', 'DD-MM-YYYY') - 1) excel_date
   from dual;

Source: https://community.oracle.com/thread/1127089?tstart=0