Reduce a PDF's file size choosing between high quality, balanced or smallest size. Free, unlimited, and no file ever gets uploaded to a server.
100% private: everything runs on your computer, your files never leave your device.
Compress PDF makes a document smaller by re-encoding the images inside it, on your own computer. The file is opened in the browser tab, the embedded images are decoded, resized and saved again as JPEG at the quality you choose, and the document is written back out. Nothing else is rebuilt: the text stays as text, vector graphics stay as vectors, and the page structure is left alone.
That is what decides how much you save. A PDF made of scanned pages or photographs can lose most of its weight, because almost all of it is image data. A PDF that is mostly text was never heavy because of its images, so the saving is small, and the result screen says so instead of pretending otherwise. When a recompressed image would not come out at least ten per cent smaller than the original, OléPDF keeps the original and moves on to the next one.
The output is a normal PDF. It opens in any reader, the text can still be selected and searched, and the pages keep their size, order and rotation.
A level is just a pair of numbers: the JPEG quality the images are saved at, and the longest side they are allowed to keep. Everything else is identical between the three.
The PDF is read, decoded and rewritten by a library running inside your browser tab. The document is never uploaded, no page is sent anywhere to be analysed, and no third-party script is loaded. The only thing your browser downloads is OléPDF's own code, from OléPDF's own domain.
When you close the tab, the only copies of the document are the ones on your disk. That is what makes the tool usable for the files people normally need to shrink: signed contracts, medical scans, tenders and internal reports.
Yes. Compressing one PDF at a time is free and unlimited, with no account and no watermark on the pages. Processing several files in a single run requires the 7-Day Pass or Pro.
The images lose quality, by exactly as much as the level you pick. Text and vector graphics lose nothing: they are not re-encoded at all, so they stay sharp at any zoom and remain selectable.
Because its weight was not in its images. A text document, or one whose images were already compressed hard, has little left to squeeze. OléPDF also keeps the original image whenever recompressing it would not save at least ten per cent, so it never makes a file worse.
No. The whole process happens in your browser, on your computer. The PDF never reaches a server.
It reorders the internal structure of the PDF so that a reader can display the first page while the rest of the file is still arriving. It does not change a single pixel; it only helps a document open faster over a slow connection.
Not directly. Remove the password with Decrypt PDF first, then compress the unlocked copy.