Convert PDF to grayscale

No. The file is rewritten, not rendered: every colour operator in the page content becomes its grey value, images are converted in place, gradients get grey colour functions. Text stays text - sharp at any zoom, selectable, searchable - and bookmarks, links and forms survive.

As the PDF standard recommends: 0.299 × red + 0.587 × green + 0.114 × blue, which is how the eye weighs the three; CMYK goes through the same weights plus the black channel. Dark red and dark blue come out as different greys, as they would on a black-and-white printer.

Usually a little smaller. JPEG photos are re-encoded at the same size class, and raw images lose two thirds of their bytes as one channel replaces three. A file that carries a JPEG 2000 or 16-bit image keeps it in colour - the tool says so.

Nothing is uploaded: the file is opened and processed inside your browser and never leaves your device. Close the tab and it is gone.

No - the colour values are replaced in the file, so keep the original if you may need it. The saved copy is a new file; the one you loaded is untouched on your device.

A printer converts as it prints, and only for that print. This changes the document, so everyone who opens it sees grey - which is what a print shop's black-and-white job, a two-colour submission rule or an e-mail that must not look like a colour brochure actually needs.

Yes. Drop in a .docx, .xlsx or .pptx file or an image (JPG, PNG, WebP...) and it is turned into a PDF in your browser as it arrives - an image onto an A4 page - then handled like any other PDF; nothing is uploaded. The conversion is our own, so the result can differ slightly from Office's own PDF export: a font may be substituted and charts are left out. The file list shows a warning when something couldn't be carried over.