Compress PDF

No. The PDF is read and recompressed entirely in your browser using your device's own resources. Nothing is sent to a server, and nothing is stored after you close the tab.

Each page is rendered to an image and re-encoded as a JPEG at a lower quality and, for stronger levels, a smaller resolution. The pages are then assembled into a new PDF. This is most effective on scanned or image-heavy documents.

No. Because every page is turned into an image, the result is a picture of each page rather than live text — you cannot select, search, or copy text in the compressed file. Keep the original if you need editable or searchable text.

Text-only or already-optimised PDFs can come out the same size or larger once their pages are rasterised, since vector text compresses better than an image of it. When that happens the tool tells you and you should keep your original file.