RunLocalTools

Convert a PDF to Grayscale — Free, in Your Browser

Turn a color PDF into true grayscale, page by page, with the pages you skip kept at full original quality. Free, private, no upload required.

What it does

This tool converts a color PDF to grayscale. You choose which pages get converted — anything outside that range is copied straight through at its original quality, still full color, still selectable text — so you’re never forced to flatten pages you didn’t ask to change.

How it works

Each page you choose to convert is rendered at a resolution you control (100–300 DPI), then every pixel is converted using the same luminance-weighted formula used in print and broadcast (0.299×red + 0.587×green + 0.114×blue) rather than a flat average of the three channels — a flat average tends to make blues look too bright and greens too dark compared to how the eye actually perceives brightness, so the weighted formula produces a result closer to what you’d expect from a proper black-and-white conversion. The grayscale pages are then re-embedded as either JPEG (smaller, better for scanned pages and photos) or PNG (crisper for dense text) inside a freshly built PDF, while any pages left out of your range are copied over using the original PDF’s own vector page data, completely unchanged.

How to use it

  1. Drop in one or more PDFs.
  2. Choose a resolution — 150 DPI is a good default for most documents, 300 DPI if you need print quality.
  3. Pick JPEG or PNG for the converted pages, and a JPEG quality level if applicable.
  4. Leave “Pages to convert” as all, or enter something like 2-10,15 to grayscale only specific pages.
  5. Convert and download — batches of multiple files can be downloaded together as a .zip.

FAQ

Will this make my file smaller? Usually yes for photo-heavy pages, since grayscale JPEGs compress better than color ones. Very text-heavy pages may actually grow, since the original vector text is being replaced with a rasterized image — if that matters to you, keep the resolution setting reasonable rather than maxing it out.

Can I keep some pages in full color? Yes — that’s the point of the page range setting. Anything outside your chosen range is left completely untouched, not even re-rendered.

Will the text still be selectable after converting? Only on pages you leave outside the conversion range. Pages that get grayscaled are rasterized as part of the conversion — there’s no way to shift color values of arbitrary vector text and embedded images without rendering the page, in any browser-based tool.

What resolution should I pick? 150 DPI looks good on screen and keeps files small. Go to 300 DPI if you’re printing the result or the original has fine text you want to stay sharp.

Does this work on scanned PDFs? Yes — in fact scanned/photographed pages are exactly the case where this kind of conversion looks best, since they’re already images and lose nothing by being re-rendered.

If you want more than grayscale — an aged, photocopied look with skew and paper grain — run the result through our scanned-look tool afterward. And if what you actually need is individual grayscale image files rather than a PDF, convert the pages first with our PDF ↔ image tool.