Compress PDF
Shrink a PDF by recompressing its streams and images. Drop as many as you like.
Runs on your device. The file is never uploaded.
Compress PDF hands your file to qpdf, which optimises embedded images, generates object streams and re-runs Flate over the rest, and the result carries a -compressed suffix. The pass is lossless, so pages are never rasterised. When the rewrite lands larger than the original, your own bytes come back and the report says already optimal.
Questions
How much smaller will my PDF get?
It depends entirely on what is inside. Scans and image-heavy documents can drop substantially; a text-only PDF that was already saved efficiently might not shrink at all. The tool runs qpdf with image optimisation, object streams and Flate recompression, and reports what happened.
Will it make my PDF blurry?
No. This is lossless recompression, it repacks the streams and structure of the file, and does not rasterise pages or throw away image detail. A tool that hits a target size by degrading images would be a different tool, not a setting on this one.
Why did I get my file back the same size?
Because compression lost. Object streams and a cross-reference stream carry fixed overhead that, on a small PDF, can cost more than the recompression saves. Rather than hand back something larger, the tool keeps your original bytes and says so: "already optimal, returned unchanged".
Why are there no quality settings?
Because there is nothing honest to put on the slider. The win here is qpdf's lossless pass, which is either available or not; a "compression level" would be a dial over one boolean.
Can I compress a password-protected PDF?
No, and it says so rather than failing quietly: "password-protected, unlock it first". Run Unlock PDF with the password, compress the result, then protect it again if you need to.
Can I compress a folder of PDFs at once?
Yes. Drop as many as you like, each is compressed separately and comes back as its own file, named with a -compressed suffix.