Compress PDF

The rewrite happens in this tab and nothing uploads. How much you save depends on where the bytes live: documents written the old way, with loose cross-reference tables and unused objects, shrink the most. Scans and image-heavy PDFs keep their size in image data, so the lossless pass moves them little or not at all, and the result says so honestly instead of promising a percentage.

What this does not do: there is no image downsampling and no quality dial, because both would throw data away. If you need a much smaller scan, downsample the images first, then run this pass to trim the structure. Encrypted PDFs are refused; decrypt a copy first.