Compress PDF
Reduce PDF file size by optimizing and rebuilding the document. Free, private, in-browser.
How to use this tool
- Drop a PDF into the dropzone.
- Choose a compression level (Low / Medium / High).
- Click Compress PDF and wait for the re-encoding.
- Download the smaller file and compare sizes.
How it works
The PDF is parsed with PDF.js, pages are rendered, and the document is rebuilt with PDF-lib while embedding re-compressed images at the chosen JPEG quality.
Tips
- Use High compression for scans that will only be read on screen.
- Keep it Low for files that will be printed.
Limitations
Vector elements remain vector; real size gains come mostly from images. Complex files may render slightly differently after rebuild.
Frequently asked questions
Does compression reduce quality?
The tool rebuilds the document and re-encodes embedded images at your chosen quality level. Lower quality produces smaller files.
Which PDFs shrink the most?
Image-heavy PDFs (scans, photos) shrink dramatically. Text-only PDFs are already small and won't shrink much.
Is this the same as an online optimizer that uploads?
No. This runs in your browser — the file is never uploaded.
Is there a limit?
Very large PDFs may be slow because processing is local; files under 200 MB work smoothly.