Compress PDF
Add your PDF file, choose any options you need, and DOC321 prepares the PDF result for you.
Choose a PDF file
Processing is performed by the browser-based PDF engine.
Choose a PDF file to begin.
Compress PDF files directly in your browser with QPDF-based stream and object compression, then download the smaller PDF when size reduction is possible.
Free Compress PDF
Works with PDF
Get a usable PDF result
Free Compress PDF: Reduce PDF File Size Online
Compress PDF files directly in your browser with QPDF-based stream and object compression, then download the smaller PDF when size reduction is possible. It is also useful for compressing PDF when you want the same task handled in one straightforward browser workflow.
Browser-based QPDF compression
The tool rebuilds PDF object and stream structures using the QPDF WebAssembly engine.
Choose a compression level
Low, medium, and high settings control stream recompression effort without rasterizing every page.
No fake savings
If the PDF cannot actually be made smaller, the tool reports that instead of returning a larger file as a compressed result.
How to Use Compress PDF
- 1Add PDF
Choose the file or content you want to work with in the hero workspace, or drag it into the upload area.
- 2Choose your options
Set only what is necessary for the result you want.
- 3Run Compress PDF
Reduce PDF file size
- 4Use PDF
Review the result, download it, or continue into a closely related workflow.
Compress PDF for Everyday Workflows
Purpose-built action
Compress PDF is designed around the specific task people come to the page to finish.
Focused workflow
Everything on the page is organized around one job: reduce PDF file size.
Clear source and result
Know what goes in as PDF and what you should expect back as PDF.
Built for everyday files
Use the tool for school, office, personal, client, publishing, and administrative document tasks.
Easy to review
Check the result before you download, share, submit, print, publish, or continue into another tool.
Easy next step
Related DOC321 tools stay close by when the finished file needs another conversion, edit, or document action.
FAQs About Compress PDF
How do I reduce PDF file size?
Choose a PDF, select a compression level, then run Compress PDF. A download appears only when the resulting file is smaller.
Does compression lower image quality?
This compressor focuses on PDF object and stream compression. It does not intentionally rasterize every page at a lower image resolution.
Why can some PDFs not be compressed further?
Some PDFs are already optimized or mostly contain data that QPDF cannot reduce without destructive recompression.
What does Compress PDF do?
Compress PDF is designed to reduce PDF file size. The page keeps that task, the supported PDF input, and the PDF result together in one browser workflow.
Can I use Compress PDF online for free?
Yes. DOC321 provides Compress PDF as a free online browser tool so you can start the supported workflow from the page without installing a separate desktop application.
Document Work Made Easier
Finished with Compress PDF? DOC321 keeps related PDF, Word, image, spreadsheet, presentation, text, and document tools close so you can continue the workflow without starting over.
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