Make a PDF small enough to email or upload. Pick a balance of size and quality below — image-heavy PDFs (scans, photos) shrink the most.
This compressor rebuilds the PDF by rendering each page to an image and re-encoding it as a JPEG at the chosen quality, which is exactly where the bulk of most PDF files lives. Scanned documents and photo-heavy PDFs often shrink by 60–90%. A PDF that is already mostly text has little image data to squeeze, so it may barely change — the result line always shows the before and after sizes so the saving is honest. Pages keep their original dimensions and reading order.
Will text stay selectable? No — after compression, pages are images, so text cannot be selected or searched. Keep the original if that matters; use the High quality setting for the sharpest result.
Is there a file size limit? There is no set limit, but very large PDFs (hundreds of pages) can take a while and use a lot of memory, because everything happens on the device. A desktop browser handles big files best.