The other similar question is not related to my question and didn't provide answers at all.

So I'm looking for a freeware or opensource software that can compress my 1GB+ PDF files into a reasonable size, without quality loss or very little quality loss...

  • 3
    Can you please provide the link to the other similar question?
    – quintumnia
    Jun 6, 2017 at 9:36
  • 2
    What is a reasonable size? What do you have in your document, Only text? Is it realy text or it is vectorized? What is the intended usage from the output?
    – Rafael
    Jun 6, 2017 at 11:05
  • 4
    What OS should it run on?
    – Izzy
    Jun 6, 2017 at 15:25
  • @quintumnia maybe it was GUI software to compress and merge PDFs
    – kirogasa
    Jan 23, 2023 at 9:53

5 Answers 5


Portable Document File PDF Compressor

It Compresses PDF Files & Reduce PDF File Size Easily

There are lots of PDF files need to be copied, transferred or exchanged often on the Internet. However, PDF documents are made from images and the file sizes are very large. It is not easy to send emails with large PDF attachments.

PDF Compressor is a Windows utility that compresses scanned PDF files and reduces PDF file size from 30 MB to only 8 MB (Compression Ratio: 23%) fast and easily. This tool allows users to change the compressing value to get better compressed result and content quality. Also, the program supports batch mode and lets users compress hundreds of PDF documents at one time.

PDF Compressor can save the compressed PDF documents to original PDF folder without overwriting original PDF files. But if you like, it can also output compressed files to a specified folder path.

The program can automatically remove the restriction from protected PDF files as well.


I use PDF24 PDF Creator for compressing PDF files.

PDF24 Compress

  • Works like a charm. Also keeps the table of contents when compressed, cool!
    – kirogasa
    Jan 23, 2023 at 9:49

I had a very good experience with Ghostscript (released under AGPL license). once installed, can be easily invoked using the command-line with parameters.

check this stackoverflow question for usage example


Since you did not specify OS, the Mac PDF viewer Preview has an option to reduce size. Use the export command and then choose 'reduce size' option.


If you are looking for good PDF optimization software I would recommend to check ORPALIS PDF Reducer Free Edition. The software can reduce PDF files up to 80%. PDF Reducer applies the most effective compression scheme based on data type. Documents are printable and zoomable without loss of quality. It's easy to use and can work in threads.

The second option I would advise is FileOptimizer created by Javier Gutiérrez. The program is a GUI for opensource and free software that can optimize files like graphics, documents, pdf files etc. This all in one solution is my must have.

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