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Xlsm file lot smaller than xls file


We are using the same aspose code to generate xls and xlsm file from a new xls template.
The file of xls file is 2mb but xlsx/xlsm file is 500 kb ( 4 times smaller).

With the old xls template the file difference is say xls:700 kb/ xlsm[x] 500 kb.

What might have gone wrong in the new xls template that causes the generate xls file to become larger by 4 times?

Let me know if I need to provide extra data.

ASPOSE version : 16.10/16.11

Hi Naren,

Thank you for contacting Aspose support.

First of all, please note that there is a vast difference in internal structures of XLS & XLSX/XLSM file formats. XLS is a binary format which tends to occupy more disc space whereas the XLSX & XLSM are Open Office XML formats therefore the file sizes of XLS & XLSX/XLSM are not comparable.

It is quite possible that a XLS of size 2MB can be saved in a few KB of XLSX/XLSM because the later formats occupy lesser disc space due to their compressed format. You can simply change the extension from XLSX/XLSM to ZIP and inspect the file contents in any Zip utility such as WinZip or WinRAR, you will notice both XLSX & XLSM comprises of a bunch of XML files.

Hope this helps a bit.