http://www.perlmonks.org?node_id=1003088


in reply to Excel file format problem Generated by Excel::writer::xlsx moduls

If you click on the green mark, Excel will probably give you a message letting you know that the cell contains a number in text format. Try doing "write_number" for those cells, instead of "write_string". Excel can be very annoying about how it deals with text formatted numbers. How it deals with time formatting is even worse...