Choosing a compression level
- Light (lossless) — rebuilds the PDF with efficient object streams. Text stays selectable, images stay untouched. Typical saving: 5–20%, best on files exported by bloated tools.
- Strong — renders each page to an image and rebuilds the PDF. Typical saving: 50–90% on scanned or photo-heavy documents. The trade-off: text is no longer selectable or searchable, and fine print can soften. Great for emailing a scan; wrong choice for a contract you need to search.
Why some PDFs don't compress
A PDF that already contains tightly compressed JPEG images has almost nothing left to squeeze — the content is already near its entropy limit. In those cases light compression still helps a little by removing redundant structure, and strong compression trades quality for size. We show you the actual numbers either way.
Frequently asked questions
Will compression damage my document?
Light compression is mathematically lossless. Strong compression re-encodes page images as JPEG — visually fine at the balanced setting, but it does discard some detail, which is why the level is your choice.
Can I compress a scanned PDF?
Yes — scans are exactly where strong compression shines, because the page images usually carry far more resolution than needed for reading on screen.
Is there a file size limit?
No limit from us. Very large files simply take longer and need more memory, because everything runs on your own device.