Reduce PDF file size in your browser
Supports PDFs up to 2,000 pages (files up to 700 MB). Compression runs in the background — this tab stays responsive.
Click or drop a PDF here
PDF Compress rewrites your PDF's internal structure entirely in your browser using the pdf-lib library, condensing its objects into compact object streams — your file is never uploaded to a server. Compression runs in a background Web Worker so the page stays responsive. It does not re-encode or downsample images, so savings are typically modest and depend heavily on the source file.
Is PDF Compress free to use?
Yes, it's completely free with no signup required.
How much can I reduce my PDF's file size?
It varies widely. PDFs with many pages, fonts, or objects tend to benefit most from the streamlined internal structure; already-optimized or small PDFs may shrink only slightly.
Does it reduce image quality?
No — images are left untouched rather than re-encoded, so visual quality is unaffected. That also means it won't meaningfully shrink files whose size mostly comes from large embedded images.
Is my PDF uploaded to a server?
No. Compression happens entirely in your browser using the pdf-lib library, in a background Web Worker.
Is there a page or file-size limit?
Yes: up to 2,000 pages and 700 MB on desktop (300 pages / 100 MB on phones and tablets) -- measured limits to keep compression reliable in the browser tab rather than risking a crash on an extremely large PDF.