--- title: "PDF to Grayscale Online Free โ€” Black & White | PDFWix" url: https://www.pdfwix.com/grayscale-pdf description: "Convert a colour PDF to grayscale black and white to save printer ink and shrink file size. Three quality presets included. Free, private, in your browser." lang: en --- Skip to content All tools (https://www.pdfwix.com/) # Convert PDF to Grayscale Online Free (Black & White PDF) Convert a colour PDF to black and white to print without colour ink, meet monochrome submission rules, and cut file size. Free, private, runs in your browser. Updated July 2026 ยท Reviewed by the PDFWix Team (https://www.pdfwix.com/about/team) Converting a PDF to grayscale replaces every colour with a shade of grey using the BT.709 luminance formula, so text stays sharp and photos keep their contrast. A grayscale PDF prints without touching colour ink or toner, satisfies portals that require black-and-white submissions, and is usually far smaller than the colour original. PDFWix converts each page in your browser at 150 DPI, 300 DPI or high-contrast black and white. To convert a PDF to grayscale free: open PDFWix Grayscale PDF, drop in the file, pick Standard 150 DPI, High-resolution print 300 DPI or high-contrast scanned document, then click Convert to Grayscale and download. Every page becomes black and white, so printing uses no colour ink. Conversion runs in your browser. 0 of 3 free conversions used today or drop PDFs here Pages are re-drawn as grayscale images, so text stays sharp but is no longer selectable. Keep the original if you still need to copy text from it. Want this in your History? Free account keeps your last 30 jobs (filename + tool only โ€” never your files) so you can re-find them later. Create free account โ†’: https://www.pdfwix.com/auth?tab=signup ## Common next steps Compress PDF Reduce file size while keeping the best quality possible. https://www.pdfwix.com/compress-pdf PDF to JPG Convert each PDF page into a JPG, or extract images from PDFs. https://www.pdfwix.com/pdf-to-jpg Repair PDF Repair a damaged PDF and recover data from corrupt files. https://www.pdfwix.com/repair-pdf ๐Ÿ”’ HTTPS ยท Browser-side processing ยท 100% free ## How grayscale conversion works, and what it costs you Greyscale is not simply "colour turned off". Each pixel's three colour channels are collapsed into a single brightness value using the BT.709 luminance weights โ€” roughly 21% red, 72% green, 7% blue โ€” which match how human vision responds to each channel. A naive average would turn red headings into muddy mid-grey and wash out yellow highlights; luminance weighting keeps coloured text and chart lines distinguishable from the page behind them. The trade-off is worth knowing before you convert. PDFWix re-draws every page as a grayscale image and rebuilds the PDF at the original page size, which guarantees that no colour survives anywhere in the file โ€” including inside embedded images, logos and background tints that colour-managed printers otherwise reproduce with coloured toner. Because the page becomes an image, the text in the output is no longer selectable or searchable, so keep the colour original if you still need to copy from it. Pick 300 DPI whenever the file will be printed and read closely; 150 DPI is plenty for screen reading and everyday office printing, and produces a much smaller file. ## How to convert a PDF to grayscale 1. 1 ### Upload your colour PDF Drag the file into the upload box or click to select it. Reports, scans, slide decks and brochures all work. 2. 2 ### Choose a quality preset Standard 150 DPI for email and office printing, High-resolution print 300 DPI for close reading, or high-contrast for scanned paperwork. 3. 3 ### Click Convert to Grayscale Each page is re-drawn in shades of grey in your browser, with page-by-page progress for long documents. 4. 4 ### Download the black-and-white PDF Save the converted file. Your colour original stays untouched on your device. ## Tips for grayscale PDFs ### Keep the colour original The converted pages are images, so text is no longer selectable. Keep the original if you still need to copy from it or run OCR (https://www.pdfwix.com/ocr-pdf) later. ### Use 300 DPI for anything printed 150 DPI looks fine on screen but small print can soften on paper. Pick the print preset for filings and bound documents. ### High contrast is for scans, not photos The scanned-document preset forces pure black and white, which sharpens faxed paperwork but flattens photographs. ### Check colour-coded charts first If a chart relies on colour alone to distinguish series, label it before converting โ€” greyscale cannot recover that distinction. 150 DPI ยท 300 DPI ยท high contrast Presets None Colour left in the file 100% in your browser Processing Results measured on a sample of 500 PDFs across scanned documents, photo portfolios, and office reports. ## Grayscale conversion vs printing in black and white | Method | Colour removed from file | Same result on every printer | Smaller file | Text stays selectable | | --- | --- | --- | --- | --- | | PDFWix Grayscale PDF | โœ“ Yes | โœ“ Yes | Usually yes | โœ— No | | Printer greyscale setting | โœ— No | โœ— Depends on driver | โœ— No | โœ“ Yes | | Screenshot each page | โœ“ Yes | โœ“ Yes | โœ— Often larger | โœ— No | | [Compress PDF](/compress-pdf) | โœ— No | n/a | โœ“ Yes | โœ“ Yes | Why converting the file differs from ticking greyscale in the print dialog. ## Why convert a PDF to grayscale Converting the file itself is the only way to be certain no colour reaches the printer or the reviewer. - **No colour ink or toner used.** Colour cartridges cost far more per page than black. A grayscale PDF prints from the black cartridge alone, even on printers that default to colour for anything with a tinted logo. - **Meets monochrome submission rules.** Court filings, patent offices, tender portals and many university print shops require black-and-white PDFs. Converting the file guarantees compliance instead of relying on a print setting. - **Smaller files.** Dropping the colour channels usually cuts file size noticeably at 150 DPI, which helps with upload limits and email attachments. - **Readable, not muddy.** BT.709 luminance weighting keeps coloured headings, chart lines and highlights distinguishable, unlike a plain channel average. - **Nothing is uploaded.** Conversion runs inside your browser tab, so confidential filings and medical records never leave your device. If your goal is purely a smaller file rather than black and white, try Compress PDF (https://www.pdfwix.com/compress-pdf) first โ€” it keeps colour and keeps text selectable. If you only need a smaller file, start with Compress PDF (https://www.pdfwix.com/compress-pdf). To save individual pages as images instead, use PDF to JPG (https://www.pdfwix.com/pdf-to-jpg), and to combine several documents before converting use Merge PDF (https://www.pdfwix.com/merge-pdf). ## When a grayscale PDF is the right choice - Printing a long report or thesis without burning through colour toner - Preparing court filings and patent submissions that must be black and white - Cleaning up a colour-tinted scan into high-contrast, readable paperwork - Sending a lighter version of a colour brochure by email - Archiving documents where colour carries no information - Converting to grayscale, then running Compress PDF (https://www.pdfwix.com/compress-pdf) to squeeze the file under an upload cap ## Frequently asked questions ### Is converting a PDF to grayscale free? Yes. PDFWix converts PDFs to grayscale for free with no watermark on the output. ### Will a grayscale PDF print without colour ink? Yes. There is no colour data left in the file, so even a colour printer uses only the black cartridge. ### Does grayscale conversion reduce file size? Usually. At 150 DPI the file is typically smaller than the colour original; at 300 DPI it may be similar in size but far cheaper to print. ### Can I still select text after converting? No. Pages are re-drawn as grayscale images, so text becomes part of the picture. Keep the colour original if you need selectable text. ### What is the difference between grayscale and black and white? Grayscale keeps shades of grey, so photos still look natural. The high-contrast preset forces pure black or white, which suits scanned text and line drawings. ### Which DPI should I choose? 150 DPI for screen reading, email and everyday office printing; 300 DPI when the document will be printed and read closely, such as a filing or thesis. ### Are my files uploaded? No. Rendering and conversion happen inside your browser, so the PDF stays on your device. ### Can I convert a PDF to grayscale on my phone? Yes, in any modern mobile browser. Very long documents at 300 DPI are faster and more reliable on a desktop. ## More PDF tools ### Compress PDF ### PDF to JPG ### Repair PDF ### Merge PDF Combine PDFs in the order you want with the easiest PDF merger. https://www.pdfwix.com/merge-pdf ## Related PDF tools Compress PDF: https://www.pdfwix.com/compress-pdf PDF to JPG: https://www.pdfwix.com/pdf-to-jpg Repair PDF: https://www.pdfwix.com/repair-pdf Merge PDF: https://www.pdfwix.com/merge-pdf Split PDF: https://www.pdfwix.com/split-pdf Remove Pages: https://www.pdfwix.com/remove-pages ## Structured data ```json [ { "@context": "https://schema.org", "@type": "WebApplication", "name": "Grayscale PDF โ€” PDFWix", "applicationCategory": "UtilitiesApplication", "applicationSubCategory": "PDFApplication", "operatingSystem": "Any", "browserRequirements": "Requires a modern web browser", "offers": { "@type": "Offer", "price": "0", "priceCurrency": "USD", "description": "Free, no signup required" }, "aggregateRating": { "@type": "AggregateRating", "ratingValue": "4.8", "ratingCount": "1364", "bestRating": "5", "worstRating": "1" }, "description": "Convert a colour PDF to grayscale black and white to save printer ink and shrink file size. 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