Grayscale PDFs are smaller, cheaper to print, and required in several professional contexts from academic publishing to government archiving. Our tool renders each page via PDF.js and applies a luminance conversion (standard ITU-R BT.601 coefficients) before re-embedding the pages into a clean PDF.
PDF PDF
Free PDF to Grayscale Converter — Black & White PDF
Free online PDF → PDF converter. Runs entirely in your browser — your files are never uploaded to a server.
No file upload
No signup
10 free/day
WebAssembly speed
How to convert PDF to PDF
- Upload PDF Drag and drop or click to browse. Files stay on your device — never uploaded.
- Convert WebAssembly runs the conversion at native speed inside your tab. No waiting for a server.
- Download PDF Click Download. Your PDF file saves directly to your device.
Frequently Asked Questions
Does converting to grayscale reduce the PDF file size?
Yes, significantly. Colour image data requires three colour channels (R, G, B) per pixel. Grayscale uses one channel. For PDFs with embedded colour photographs, converting to grayscale can reduce file size by 30–60%. PDFs with text and vector graphics see smaller but still meaningful reductions.
Can I convert back to colour after grayscale conversion?
No. Converting to grayscale is a one-way operation. Colour information is permanently discarded during the conversion. If you need to preserve the original colours, keep a backup of the original PDF. We recommend keeping the original and distributing the grayscale version for printing.
Why would I want a grayscale PDF?
Common reasons include: printing on black-and-white printers without expensive colour ink, reducing file size for email attachments, meeting accessibility requirements for high-contrast printing, and producing print-ready PDFs for black-and-white publications. Grayscale is also required by some archival standards for document storage.
Looking for another format?
Browse all 400+ converters