Quick answer: to convert a PDF to grayscale, open it on this page, check the before-and-after preview and press Convert & download. The default mode keeps text sharp and selectable. If a print shop or an online form needs a file with no colour data, choose Print-ready. Nothing is uploaded: the conversion runs in your browser.
Key facts
- Price: free, with no account, no watermark and no page limit.
- Privacy: the PDF is converted on your device and never uploaded.
- Two modes: Keep text sharp for reading and sharing, Print-ready for professional printing and strict upload rules.
- Pure black and white: print-ready mode can also turn pages into crisp black-on-white, ideal for scanned text.
- Works on: phones, tablets and computers, in any modern browser.
How to convert a PDF to black and white
- Open your PDF. Click Select PDF file or drop the file onto the page. The first page appears in grey.
- Choose how to convert. Keep Keep text sharp for everyday use, or switch to Print-ready and pick Grayscale or Black & white and a quality.
- Compare. Press Show original to flip between the colour page and the result, and use the arrows to check other pages.
- Download. Press Convert & download. The new file ends in “-grayscale”, and your original stays unchanged.
Which mode should I choose?
| Keep text sharp | Print-ready | |
|---|---|---|
| Looks grey on screen and on paper | Yes | Yes |
| Text can be selected, copied and searched | Yes | No, pages become images |
| File size | About the same as the original | Depends on quality; often larger for text documents, often smaller for photo-heavy ones |
| Colour information left in the file | Yes, hidden under the grey layer | None at all |
| Best for | Reading, sharing, home and office printing, e-readers | Print shops, publishers, portals that reject colour files, scanned documents |
In short: if a person will read the file, keep text sharp. If a machine or a printing company will check the file for colour, choose print-ready.
Why convert a PDF to grayscale?
- Save colour ink and toner. Many printers still use some colour ink for “black” on colour pages. A grayscale file prints with black only on most printers.
- Printing rules. Universities, courts, exam boards and print shops often ask for black-and-white submissions, for example a thesis printed in grayscale except for the colour pages you list.
- Cheaper printing. Print shops and copy centres usually charge less per page for black and white.
- Easier-to-read scans. Phone scans and photocopies often have a yellow or blue tint. Pure black and white removes the tint and makes the text stand out.
- E-ink readers. Kindle and other e-ink screens show grey anyway; converting first lets you check contrast before you transfer the file.
- A cleaner look. A colourful report or slide deck can look more formal in grey.
Grayscale or black and white: what's the difference?
Grayscale keeps every shade between white and black, so photos, charts and shaded tables still look natural. Black and white (sometimes called monochrome or bitonal) uses only two colours: each dot is either black or white. That is perfect for typed text and line drawings and makes scanned pages very crisp, but it turns photos into harsh shapes. Use the Threshold slider to decide how light a mark can be and still print as black: lower values remove faint background noise, higher values keep light pencil and stamps.
How the conversion works
In Keep text sharp mode, CleanPDF does not redraw your pages. It adds a single colour-removing layer on top of each page, using a standard PDF blending feature. Underneath, every word is still real text and every chart is still sharp vector graphics, which is why you can still search and copy the text. In Print-ready mode, each page is rendered at the quality you choose, converted to grey using the standard luminance formula that print workflows use, and stored as an image. A file made this way contains no colour data at all.
Privacy and security
Your PDF is opened, converted and saved inside your browser. It is not uploaded to a server, stored or seen by anyone, so you can safely convert contracts, medical letters, bank statements and ID documents. No account is needed and nothing is added to your file.
Good to know
- Your original file is not changed. You always download a new copy.
- Keep text sharp uses a blending feature that has been part of the PDF standard since 2001, so modern viewers and printers show the pages in grey. Because the colour data is still inside the file, a professional preflight check may still report it as colour, and a very old viewer could show colour. Use print-ready in those cases.
- Print-ready files are images. If you need searchable text afterwards, run the result through PDF to Text (OCR).
- Large or long documents: print-ready mode at 300 dpi takes longer and creates bigger files. 150–200 dpi is plenty for office printing.
- Password-protected PDFs must be unlocked first with Unlock PDF.
Frequently asked questions
How do I convert a colour PDF to black and white for free?
Open the PDF on this page and press Convert & download. The pages turn grey while the text stays sharp. It is free, with no sign-up and no watermark.
Will the text still be selectable after converting to grayscale?
Yes, in the default Keep text sharp mode. The text stays real text that you can select, copy and search. In Print-ready mode the pages become images and the text is no longer selectable.
Is my PDF uploaded anywhere?
No. The conversion runs in your browser on your own device, so the file is never uploaded or stored.
How do I make a PDF print in black and white only?
Convert it here first. A grayscale PDF prints with black ink or toner on most printers, even when the printer's colour setting is left on.
What is the difference between grayscale and black and white?
Grayscale keeps all the shades of grey, so photos look natural. Black and white uses only pure black and pure white, which makes text and scans crisp but turns photos into high-contrast shapes.
My print shop says my file still has colour. What should I do?
Convert it again with Print-ready. That mode rebuilds every page as a grey image, so the file contains no colour information at all.
Will converting to grayscale make my PDF smaller?
Keep text sharp keeps the size about the same. Print-ready can make photo-heavy files smaller and text-only files larger. Use Compress PDF afterwards if you need a smaller file.
How do I clean up a scanned PDF that looks yellow or blurry?
Choose Print-ready, then Black & white, and move the Threshold slider until the text is dark and the background is clean white. Check a few pages with the arrows before downloading.
Can I convert only some pages to grayscale?
The tool converts the whole document. To keep a few pages in colour, convert a copy, then use Delete PDF Pages and Merge PDF to combine the colour and grey pages you want.
Does it work on my phone?
Yes. It works in any modern browser on Android and iPhone, as well as on tablets and computers.
Is there a file size or page limit?
There is no fixed limit. Very large documents depend on your device's memory, especially in Print-ready mode at 300 dpi.
Can I convert a password-protected PDF?
Unlock it first with Unlock PDF using its password, then convert it here.