PDF Compressor
Optimize document structure and object streams to shrink your PDF's file size, then download the result — free, private, and processed entirely in your browser.
About the PDF Compressor
Our free online PDF compressor shrinks a PDF's file size by optimizing its internal structure — restructuring the cross-reference table and object streams — without touching the page content itself. That makes it easy to fit a document under an email attachment limit or keep an archive lean, without sacrificing quality.
Unlike most online tools, compression happens entirely inside your browser using the pdf-lib library — your PDF is never uploaded to a server. That means it's fast, works without an internet round-trip, and keeps your files completely private and secure.
How to Compress a PDF
Step 1
Upload your PDF
Drag and drop a PDF file, or choose one from your device.
Step 2
Click "Compress PDF"
The tool optimizes the document structure, cross-reference tables, and object streams.
Step 3
Download the result
Download the optimized, smaller PDF file instantly — no waiting, no watermark.
Frequently Asked Questions
Will compressing my PDF reduce image quality?
No. This compressor optimizes structural streams and metadata client-side, meaning page contents and images remain completely untouched and preserve their original quality.
Is there a file size limit?
Because compression runs entirely in your browser using your local hardware, it can handle large files, but browser performance depends on your device's memory.
Why would I want to compress a PDF?
A smaller PDF is faster to upload, download, and share — which is especially helpful for email attachments that have strict size limits, or for archiving many documents efficiently.
Is my data safe?
Yes. Compression happens entirely in your browser using the pdf-lib library — your PDF is never uploaded to a server, so it stays completely private.
Does it cost money?
No. The PDF compressor is 100% free to use, with no registration or account required.