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PDF → Grayscale

Each page is rendered at your chosen DPI and converted to grayscale. The result is a raster PDF, nothing is uploaded.

How PDF to Grayscale works

PDF to Grayscale converts every page of a colour PDF into a black-and-white version by re-encoding all colour content through a luminance mapping. Text, images, vector graphics and backgrounds are all converted. The conversion runs inside your browser using a canvas-based rendering pipeline, and the PDF stays on your computer throughout. No account, no upload, no cloud service is involved.

The tool renders each page to a canvas at a high resolution, converts the RGB pixel data to grayscale using standard luminance coefficients, and encodes the result back into a PDF. This means the output pages are raster images rather than native vector content. Text and thin lines will remain legible at normal viewing sizes, but the file will not retain a selectable text layer. If you need a grayscale PDF with selectable text, a PostScript-based conversion pipeline is the more appropriate approach, but that requires server-side processing. The conversion also covers the whole document: to grayscale only part of a file, extract those pages with the PDF split tool first, convert them, then put the document back together with PDF merge.

Written by Bastien Sulyan

How to use PDF to Grayscale, step by step

  1. Drop your colour PDF onto the upload area.
  2. Choose the output resolution if the option is available, or use the default.
  3. Click convert and wait for each page to be processed.
  4. Download the grayscale PDF.

Common use cases

  • You need to print a colour report on a black-and-white printer and want to preview exactly what it will look like before printing.
  • A publication needs a grayscale version for a print run that uses only black ink, reducing printing costs.
  • An internal document contains colour charts that must be converted to grayscale to comply with accessibility standards for contrast.
  • A scanned form has coloured fields and labels; convert it to grayscale to reduce file size for archiving.

Frequently asked questions

Will the text in my PDF still be selectable after grayscale conversion?

Not with this approach. The conversion renders each page to a canvas and re-encodes it as a raster image, so the text layer is not preserved in the output. If selectable text is important, a PostScript-based conversion path is needed, which requires server-side tools.

How is the colour-to-grayscale mapping calculated?

The tool uses standard luminance coefficients from the ITU-R BT.601 formula: 0.299 for red, 0.587 for green and 0.114 for blue. This produces a perceptually balanced grayscale that matches how the human eye weights the brightness of each channel.

Will the grayscale PDF be smaller than the original?

Not necessarily. The output is a rasterised PDF, which can actually be larger than a vector-based original because each page becomes a compressed image rather than a set of coordinates and font references. File size depends on page dimensions and the chosen output resolution.

Is my colour PDF processed on a server to produce the grayscale version?

No. Every page is rendered on a canvas element inside your browser, the pixel data is converted to grayscale there, and the output PDF is assembled in browser memory. The original file is never transmitted.

Does the conversion affect embedded document metadata like the title or author?

Standard document metadata such as title, author and creation date is carried over into the output PDF. Page content is re-rendered but top-level document properties are preserved.