I am using
Custom date fields are being converted to numbers. I know that XLSX stores custom dates as serial values. I need to find the way to convert those values into dates/times.
XLSX: 10/13/2011 0:00
Excel stores dates and times as a number representing the number of days since
1900-Jan-0, plus a fractional portion of a 24 hour day:
You could write a function to do the calculations yourself or you could look at some of the modules already posted on cpan for doing this,
DateTime::Format::Excel should do what you need and
DateTimeX::Format::Excel looks like it would work too.