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How to convert and get lighter PDF output using .NET

Hi GroupDocs Support Team,

We are using groupdocs conversion API to convert a file of size 6MB and the converted PDF file was of 35MB. Original Source file and the converted PDF file is attached here for your reference.

Note:- 1.We are using function public static Stream ConvertToPdfAsStream() inside the class GroupDocsConversionUtility.cs to do the conversion.
2.Version of GroupDocs.Conversion API used is :

Can you please let us know:-
1.Is it possible to generate lighter files via GroupDocs than what we generate ?
2.Why did we see this much difference in the size of original and converted PDF file? Is 6 times larger size, an acceptable number while converting files?

Thanks and Regards
Hemant Adhupiya
Zipped content


Thanks for your inquiry. We are investigating this issue at our end, you shall be informed about the outcomes ASAP.


We are facing issue while converting the file (maybe due to large content/size of the file). Hence, we have logged this issue as an investigation in our internal issue tracking system with ID:CONVERSIONNET-2246. As we get any update form the concerned team, we shall apprise you. We’ll appreciate your patience.


We got an update from the concerned team. If you try to save/convert the problematic file to PDF using MS Excel save as or export feature, size of output file will be larger than the problematic file. However, we performed this test at our end and the size of output file was 21MB that is actually larger than 6MB source file. MS Excel optimizes the output (PDF) file (but still output file size is too greater than input/source). Our production team will work on the possibility to apply such optimization in document conversion API in any of the next version. But the expected output file size will be 20-22MB for this problematic file. Aside this, in the next version, API will do configurable conversion - to convert one sheet per page, or print area per page. We’d also recommend you to utilize latest version of the API in your project.