Turn any colour PDF into black and white grayscale. Choose render quality and which pages to convert — fast, private, and fully browser-based.
Select a colour PDF to convert to black & white — or drag & drop
Dudi Grayscale PDF is a fast, 100% free, browser-based tool from Dudi PDF Editor that converts any colour PDF into a clean black-and-white grayscale document in seconds. Whether you are preparing a colour brochure for cheap laser printing, reducing the file size of a photograph-heavy report, toning down a colour-heavy invoice for a black-and-white office printer, or creating a clean draft of a design PDF for review, this tool does all of it without installing software, creating an account, verifying an email or paying any hidden fee. Unlike most online grayscale converters, your file is never uploaded to a remote server. The entire process runs inside your browser using the well-known pdf.js and pdf-lib JavaScript libraries — your PDF is rendered page by page, every pixel is converted to grayscale using the standard luminance formula (0.299 red + 0.587 green + 0.114 blue), and the grayscale image is embedded back into a new PDF on your own device. That means your confidential reports, legal contracts, invoices, academic papers and internal company files never leave your computer or phone. There is no signup, no watermark added by us, no daily limit and no page-count restriction beyond your device's memory. Dudi Grayscale PDF gives you meaningful control over the result. A live preview shows page 1 already converted to grayscale so you can see exactly what the final PDF will look like before you convert the whole document. You can choose the render quality — 1.0× for smaller files, 1.5× for a good balance between quality and file size, or 2.0× for sharper output when you need to print. You can also target specific pages: convert all pages, odd pages only, or even pages only, which is useful when a document mixes colour advertisements with plain content pages. The output PDF preserves the original page dimensions of every page, so the document prints at the correct size without stretching or cropping. Because grayscale images contain much less colour data, the resulting file is usually 30–60% smaller than the original, and printing in grayscale can save a significant amount of ink or toner. One thing to note: the tool rasterises each page to apply the colour transformation, so the output PDF contains images rather than selectable text — perfect for printing, but not for searching or copying text. The finished file opens correctly in Adobe Acrobat, Chrome, Edge, Safari, Firefox and every common PDF reader. Because the tool never downloads automatically, nothing is saved to your disk until you choose it: after the conversion is processed, a Download button appears and you decide when to save the file. The downloaded file is always named Dudi PDF Editor Grayscale PDF.pdf, and if you convert another file in the same session it becomes Dudi PDF Editor Grayscale PDF (2).pdf and so on, so your files stay clearly identifiable. The layout is fully responsive, so the preview, quality selector and action buttons all stay easy to use on a small Android phone as well as on a large desktop monitor. After the first page load the libraries are cached, so the tool often keeps working even on a weak connection. If you need more tools, Dudi PDF Editor also offers Crop PDF, Delete Pages, Add Blank Page, Extract Images, Merge PDF, Split PDF, Rotate PDF, PDF Page Numbers, Sign PDF, Protect PDF, Unlock PDF, Watermark PDF, Word to PDF, JPG to PDF, editing, OCR, image conversion and many other privacy-first utilities that all run locally in your browser with the same no-upload guarantee.