How do I convert a PDF to grayscale?
To convert a PDF to grayscale, drop it into FixDoks's Grayscale PDF tool, pick a DPI from 100 to 300 and a quality level, then click Convert to grayscale. Each page is rendered as a black and white image and rebuilt into a PDF inside your browser, though the text is no longer selectable afterwards.
Grayscale PDF at a glance
| Input | Colour PDF |
|---|---|
| Output | Black and white PDF |
| Processing | In your browser; your files are not uploaded |
| Price | Free, no watermark |
| Download | Free Google sign-in |
| Works on | Chrome, Edge, Safari and Firefox on Windows, Mac, Android and iPhone |
How to use Grayscale PDF
- Drop your PDF onto the box.
- Pick a DPI (100, 150, 200 or 300) and a quality level.
- Click Convert to grayscale and download the black and white PDF.
How does grayscale conversion work?
To reliably turn every colour, gradient and image on a page into a clean black and white result, FixDoks rasterises each page: it renders the full page as a grayscale image at the DPI you choose, then rebuilds the PDF from those images. This is a dependable way to strip colour from complex pages that mix text, photos, tables and coloured backgrounds, since every element is treated the same way rather than trying to selectively recolour text objects and leave everything else alone.
The trade-off to know before you start
Because each page becomes an image, the text on it is no longer selectable, searchable or copyable afterwards. If you need to keep the ability to search or copy text and only care about how it looks in colour when printed, most printers already have a "print in grayscale" or "black and white" setting that avoids this trade-off entirely and is worth trying first. Use this tool when you specifically need a grayscale PDF file to hand over, upload or archive, not just a grayscale printout.
Choosing DPI and quality
| DPI | Result |
|---|---|
| 100 | Smallest file, acceptable for plain text documents. |
| 150 | Good general-purpose setting for office submissions. |
| 200 | Clearer for documents with tables or small print. |
| 300 | Best for anything that will be printed, especially diagrams or fine detail. |
File size can go either way after conversion. A PDF that was mostly plain text often gets larger, because a flat black and white image usually takes more space than tightly encoded text characters. A PDF full of large, high-resolution colour photos can shrink, especially at 100 or 150 DPI, since a grayscale raster typically needs less data than a full colour one. If the resulting file feels too large, run it through Compress PDF afterwards, or try a lower DPI.
Typical uses
- Preparing a document for an office or government submission that specifically asks for a black and white PDF.
- Cutting printing costs by converting a colour brochure or slide deck before it goes to a printer that charges more for colour pages.
- Removing colour from a scanned form so it looks consistent no matter what the original scan settings were.
Tips
If the source PDF already has poor contrast, for example a light grey scan, grayscale conversion will not improve legibility on its own; a higher DPI helps preserve detail but does not fix a badly scanned original. Keep your coloured original file if you might need it again, since this conversion cannot be reversed to recover the original colours. Test one page first if the document is long, to check the DPI gives you a look and file size you are happy with before converting the whole thing.