PDF Compression
Upload a PDF file, select a compression level, and reduce file size directly in your browser. All processing happens locally—files are never uploaded to any server.
Please upload a PDF file to start compression
How does PDF compression work?
This tool uses the pdf-lib library to process PDF files in your browser. Compression is achieved by optimizing the PDF's internal structure: using object streams to compress cross-reference tables, removing redundant and unused objects, and optimizing data structures. Note that pdf-lib has limited compression capabilities, and actual results depend on the complexity and content structure of the original PDF file.
What's the difference between the three compression levels?
Low Compression: Preserves highest quality with standard object stream compression, suitable for scenarios requiring high file integrity. Medium Compression: Balances file size and quality with additional removal of redundant metadata, ideal for everyday use. High Compression: Aims for smallest file size with deep document structure cleanup, removing unnecessary objects and metadata, perfect for storage and sharing.
Will my files be uploaded to a server?
No. All PDF compression operations are performed locally in your browser using the pdf-lib library. Files are never uploaded to any server, so you can use this tool with confidence.
What's the maximum PDF file size supported?
This tool supports uploading individual PDF files up to 100MB. Large files may take longer to process, so please be patient. We recommend keeping files under 50MB for optimal processing performance.
Related guide
How to Reduce PDF File Size Without Ruining It
Why PDFs get large, which compression level to pick for email, print, or a size-capped upload portal, and how much smaller a file can realistically get.