PDF to Greyscale
Convert a colour PDF to pure greyscale to save printer ink and file size.
Save The Colour Cartridge
Printing a colour document on a colour printer uses the colour cartridges even for text that looks black, because "rich black" is mixed from all four inks. On a long document that is a genuinely expensive habit, and most office printers will refuse to print at all once one colour runs out.
Converting to greyscale beforehand removes the question. Text and vector graphics are converted by rewriting the colour operators inside the page, which changes no layout and loses no sharpness. Photographs carry their colour in their own pixels, so those are decoded, greyed and re-encoded.
Key features
- Rewrites colour operators — text and vector art keep their exact positions and crispness.
- Rec. 601 luma weighting — the same weighting print drivers use, so the result matches what a printer would have produced.
- CMYK becomes black ink only — no colour cartridge is touched for anything that was previously coloured.
- Photos re-encoded in greyscale — usually the largest part of the file size saving.
- Honest about what it skipped — images in codecs the browser cannot re-encode are listed rather than silently left in colour.
This tool runs entirely inside your browser using native Web APIs. Your files and text are never uploaded to a server, never logged and never shared with third parties.
How to use: PDF to Greyscale
- Choose the PDF
Every embedded image is listed with its format, so you can see what will be converted. - Choose whether to convert images
Leave it on for scans and photos; turn it off to keep pictures in colour and only grey the text. - Set the image quality
Only affects re-encoded photographs. 82 is a good default for documents. - Download the greyscale copy
The before and after sizes are shown side by side.
Technical specifications
| Processing location | Entirely in your browser — no server round trip |
|---|---|
| Data uploaded | None. Files and text never leave your device |
| Price | Free — no account, no trial, no usage cap |
| Category | |
| Works offline | Yes, once the page has loaded |
| Browser support | Chrome 90+, Edge 90+, Firefox 90+, Safari 15+ |
| Interface languages | English, 中文, हिन्दी, Español, العربية |
Frequently asked questions
Why did the file not get smaller?
Greyscale saves bytes only where there were colour pixels to throw away. A text document stores its colour as a handful of operators, so converting them saves almost nothing on disk — the saving is in ink, not in bytes. Documents full of photographs typically shrink substantially.
Could I not just tick "print in greyscale" in the print dialogue?
You can, and for a one-off print that is easier. Converting the file matters when the document is being sent to someone else, archived, or printed somewhere you do not control the driver, because then the greyscale is a property of the file rather than of one print job.
Which images cannot be converted?
JPEG images convert, because the browser can decode and re-encode them. JPEG 2000, CCITT fax and JBIG2 cannot be decoded by a browser — although CCITT and JBIG2 are already one-bit black and white, so there is nothing to convert. The tool names the format it skipped rather than pretending.
Is the conversion reversible?
No. The colour information is discarded, both in the content stream and in any re-encoded image. Keep the original if you may need the colour version; this tool never modifies the file you started with.
Will the text still be selectable and searchable?
Yes. Only the colour operators change; the text operators, fonts and character codes are untouched, so selection, search and copy work exactly as before.