Compress a PDF
Reduce the size of a PDF file by re-encoding its embedded images at a reduced JPEG quality. This tool targets image-heavy PDFs (scans, photos): a PDF made mostly of text will be reduced little or not at all.
How it works
Have you scanned a contract or an administrative file with your printer or phone, and the resulting PDF weighs 40, 60, or even 100 MB? Most mail services (Gmail, Outlook…) reject attachments over 25 MB. This tool re-encodes the images embedded in the PDF (more aggressive JPEG compression, reduced resolution) to shrink the file size while keeping a readable, printable document. Choose "Screen" for quick emailing, "Ebook" for a good size/quality trade-off, or "Printer"/"Prepress" if the document still needs to be printed at high quality.
Why is my scanned PDF so heavy?
A scanner (or a mobile scanning app) saves each page as a high-resolution bitmap image, often in color even for plain black-and-white text. A 20-page document can thus weigh several dozen MB, whereas the same content as vector text would take up a few hundred KB.
Is there a visible loss of quality?
With the "Ebook" setting, the compression is noticeable when zooming in heavily on an image but remains invisible on screen or at standard print quality for a text document. For a document where image sharpness matters (plans, photos), prefer "Printer" or "Prepress", which compress less but still reduce size compared to the original.
Like all the site's tools, compression runs entirely in your browser via WebAssembly: your file is never sent to a server.