What PDF to Grayscale does
PDFGrover's PDF to Grayscale tool turns a colour PDF into a black-and-white one. Every page's colour content — images, coloured text, filled shapes — becomes shades of gray while the layout stays exactly the same.
When to convert a PDF to grayscale
- Cheaper printing — many office printers charge 5–10× more per colour page; converting first avoids the cost on long documents.
- Submission rules — some government forms and court filings require black-and-white PDFs.
- Smaller files — colour image data is roughly 3× the size of the same image in gray, so image-heavy PDFs shrink noticeably (a useful pre-step before Compress PDF).
- Consistency — checking how a document will look photocopied or printed mono.
How to convert to grayscale
- Upload a PDF — it stays on your device.
- Click Convert — every colour image is redrawn in gray and content rendered in black.
- Download the black-and-white PDF — same layout, no colour.
How it works (and the trade-off)
Each page is re-rendered into a grayscale image at a high resolution to keep text crisp while holding file size down. Because the output pages become images, selectable text on converted pages becomes part of the image — it's no longer selectable, and vector tables or diagrams are rasterised. That's the cost of a guaranteed grayscale-everywhere result.
If you need the document to stay grayscale and keep selectable text/vectors, a desktop PDF editor's colour-conversion is a better fit. For most "print it cheaply" or "the form must be B&W" needs, this tool is exactly right.
Grayscale vs Compress
To shrink a file, Compress PDF is usually the main tool — but for a colour scan of black text, converting to grayscale first, then compressing, often beats compression alone.
Limits & privacy
- One file per session
- Runs entirely in your browser — nothing uploaded, stored, or logged. The converted file exists only in your tab until you download it. No sign-up, no watermark.
Troubleshooting
- Text isn't selectable anymore — expected: converted pages are images. Keep the original if you still need selectable text.
- Barely smaller — text-only PDFs have little colour image data to shrink; the savings come from colour photos/scans.
- Looks washed out — very light colours map to light gray; that's normal for a mono conversion.