How to convert a PDF to black and white
- Drop one or more PDFs onto the box above, or click to choose them.
- Choose the Output:
- Grayscale keeps every shade of grey, so photos, charts and coloured highlights stay readable.
- Pure black and white turns each pixel either black or white. It gives the crispest text and the smallest files, which suits contracts, forms and scanned letters.
- Pick a Resolution. 150 DPI is right for reading on screen and everyday printing; choose 300 DPI if the document will be printed professionally or has small print.
- For pure black and white, adjust the threshold if needed: move it up if faint text disappears, down if a grey background turns into black blotches.
- Click Convert to black and white and download the new PDF. With several files, Download all saves them together as a ZIP.
The conversion runs entirely in your browser with Mozilla's pdf.js and pdf-lib, so the document is never uploaded.
Why convert a PDF to black and white?
- Save colour ink and toner. Many printers still use some colour ink for grey and black areas of a colour document. A true grayscale file avoids that, and some print shops charge less for black-and-white jobs.
- Meet submission rules. Courts, tax offices, universities and some employers ask for black-and-white documents or scans.
- Make scans cleaner and smaller. A phone photo of a receipt or letter often has a yellow or blue cast and a shadowy background. Pure black and white removes both and usually makes the file much smaller.
- Check how a document will look when photocopied or faxed. Colours that look different on screen can become the same grey on paper, which makes charts and highlighted text unreadable. Converting first shows you the problem.
Grayscale or pure black and white?
| Grayscale | Pure black and white | |
|---|---|---|
| Best for | Photos, charts, brochures, slides | Text documents, forms, receipts, scans |
| Shades | 256 levels of grey | Only black and white |
| File size | Medium (JPEG pages) | Usually smallest (PNG pages) |
| Risk | Low-contrast colours may look alike | Light text or photos can be lost; adjust the threshold |
Each colour is converted using its perceived brightness (the standard weighting of red, green and blue that matches how the eye sees light), so a pure yellow becomes light grey and a dark blue becomes nearly black, just as on a monochrome printer.
Things to know
- Text becomes part of the image. Every page is redrawn as a picture, so you can no longer select, copy or search the text, and links stop working. Keep the original if you need those. To get editable text back, use PDF to Word on the original file.
- A grayscale version of a text-heavy digital PDF can be larger than the original, because text stored as fonts is very compact. Pure black and white usually is not. For simply shrinking a file, try Compress PDF.
- Password-protected PDFs must be unlocked first with Unlock PDF (you need the password).
- Need images instead of a PDF? PDF to JPG exports each page as a picture.
Frequently asked questions
How do I print a PDF in black and white only?
Most print dialogs have a "Black and white" or "Grayscale" option, but printers do not always honour it, and some still mix colour inks. Converting the PDF here first guarantees the file itself contains no colour.
Will the converted PDF look blurry?
At 150 DPI text is sharp on screen and on ordinary office printers. If you zoom in a long way or print fine print, choose 200 or 300 DPI.
Why did some light text disappear in black-and-white mode?
Anything lighter than the threshold becomes white. Move the threshold slider to the right and convert again, or use Grayscale.
Is my document uploaded?
No. The PDF is opened, converted and rebuilt inside your browser, and nothing is sent to our server.