Converting a colour PDF to grayscale is the easiest way to reduce printing costs, create printer-friendly document versions, and produce archives that look consistent on any device. This guide explains how to convert a PDF to black and white for free.
The Fastest Method: Free PDF to Grayscale Converter (No Upload)
PDFWonder's PDF to Grayscale tool converts every page of your PDF to black and white entirely in your browser. No files are uploaded anywhere.
- Go to the PDF to Grayscale Converter.
- Drop your PDF onto the upload area or click to select it.
- The tool processes each page and automatically downloads the grayscale PDF.
Why Convert a PDF to Grayscale?
- Reduce printing costs: Colour printing costs 2–5× more per page than black-and-white. Converting to grayscale before printing saves significant money, especially for long documents.
- Printer compatibility: Some printers are black-and-white only. A grayscale PDF prints cleanly on monochrome printers without colour-to-grayscale translation artefacts.
- Archiving: Grayscale archives are smaller, more consistent, and render identically across all devices regardless of colour display settings.
- Accessibility: Some readers have colour vision deficiencies. A well-designed grayscale document is easier to read than a colour document that relies on colour to convey meaning.
- Professional appearance: Some formal or legal documents are expected to be black and white.
How to Convert PDF to Grayscale in Adobe Acrobat
- Open the PDF in Adobe Acrobat Pro.
- Go to Tools → Print Production → Convert Colors.
- Set the "Conversion Space" to "Gray Gamma 2.2" (or another grayscale profile).
- Set "Document Colors" to include all colour spaces.
- Click OK and save.
Note: Adobe Acrobat Pro is a paid application. The PDFWonder browser tool above is free.
How to Print a Colour PDF in Black and White (Without Converting the File)
If you only need grayscale for printing (not to save a grayscale file), you can set your printer to black-and-white mode without converting the PDF:
- Windows: Open print dialog → Printer Properties → look for "Color Mode" or "Grayscale" option → select Black & White → print.
- Mac: Open print dialog → click "Show Details" → Colour/Quality settings → select "Black & White" or "Grayscale".
- Specific printers: Most HP, Canon, and Epson printers have a grayscale print option in their advanced settings.
This does not create a grayscale PDF — it only prints in grayscale. Use the browser tool to create a grayscale PDF file.
Grayscale vs. Compressing a PDF — Not the Same Thing
Converting to grayscale removes colour but does not necessarily reduce file size. To reduce file size, use the PDF Compressor. For the best result on a large colour PDF: convert to grayscale first, then run through the compressor.
Frequently Asked Questions
Will text still be readable after converting to grayscale?
Yes. Text in the original PDF will appear as dark grey or black on a white or light grey background — perfectly readable. Only colour information is removed.
Does the output PDF have selectable text?
No — the tool renders each page as an image and embeds it in the PDF, so the output is image-based. Text will not be selectable or searchable. Keep the original PDF for text-based tasks.
How does converting to grayscale save money when printing?
Most printers charge significantly more per page for colour printing than black-and-white. Converting a colour PDF to grayscale before printing means your printer uses only black toner/ink, even if the source document was in colour.
What is the difference between grayscale and black-and-white?
Grayscale preserves shades of grey between pure black and pure white — photographs and gradients look natural. Pure black-and-white (1-bit monochrome) has no grey, only black or white pixels. The PDFWonder tool produces grayscale, which looks more natural.
Will the file size change after converting to grayscale?
The output is image-based and may be slightly larger than the original text-based PDF. Use the PDF Compressor tool afterward to reduce the file size.
Are my files uploaded anywhere?
No. All processing happens locally in your browser using PDF.js and pdf-lib. Your files never leave your device.