Free online tool
Free Online PDF Compressor — Lossless, Browser-Side
Reduce PDF file size in your browser with lossless object-stream recompression. Honest 3-10% savings on unoptimised PDFs — no fake compression claims. Free, no signup, 100% client-side.
01How it works
Upload your PDF
Drop a PDF into the upload area or click to browse. Files up to 50 MB are supported.
Click Process
The tool runs lossless object-stream recompression via pdf-lib directly in your browser. Text and images are byte-preserved — nothing is re-encoded or degraded.
Download the result
Download the compressed PDF and see the exact before/after file size. If no savings are possible, you'll see an honest 'already optimised' message.
FAQ
Frequently asked questions
How does the compression work?
This tool uses pdf-lib object-stream recompression: it strips redundant internal structures and re-serialises the document's content streams. It does NOT re-encode images — text and graphics are byte-preserved. Expect 3-10% savings on PDFs exported without optimisation, and roughly 0% on PDFs that have already been optimised.
Will compression reduce image quality?
No. This tool is lossless — text, vector graphics, and embedded images are byte-preserved. We explicitly avoid image re-encoding so you can trust the output for legal, archival, and print use. If you need aggressive image compression, use a tool that clearly advertises lossy re-encoding with a quality slider.
What happens if the compressed file is larger?
If the recompressed output would be larger than the original — which happens on already-optimised PDFs when metadata overhead grows — the tool returns the original file unchanged and reports 'already optimised' honestly rather than shipping a bigger file.
Are my files uploaded to your server?
No. The entire compression runs in your browser using pdf-lib loaded from our own vendor assets. No data is sent to a server. You can confirm this in DevTools → Network tab while the tool runs.
Need AI-powered document extraction?
This tool uses client-side processing. anyrow uses AI to extract structured data from PDFs, images, and scanned documents with 99% accuracy. 150 free extractions/month — no credit card required.