Convert a PDF to grayscale
Strip the color out of a document. Useful before mono printing, and one of the most effective ways to cut file size when compression alone isn't getting there.
- Free
- No signup
- Runs in your browser
- Nothing uploaded
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Convert a PDF to grayscale in three steps
- Add your color PDFany number of pages.
- Converteach page is re-rendered with the color removed.
- Downloada grayscale PDF, usually much smaller than the original.
What you get
Big size reductions
Dropping from three color channels to one typically takes a large bite out of a scan-heavy file.
Proper luminance conversion
Channels are weighted the way the eye perceives them, so reds don't turn into the same gray as blues.
Predictable printing
What you see is what a mono printer will produce — no surprise when a pale yellow highlight vanishes.
Limits and formats
| Method | Rec. 601 luma weighting, then JPEG encoding |
|---|---|
| Output | Grayscale PDF |
| Text | Rendered into the page image |
| Typical size change | Substantial reduction on color scans; little change on text-only files |
Common questions
Is this the same as printing in black and white?
The result is similar, but this changes the file itself rather than a print setting. It's the right approach when you're sending the document to someone else, or when you need the size reduction.
Why did my file barely shrink?
If the original was already mostly black text on white, there was little color data to remove. Grayscale conversion pays off on photographs and color scans.
Can I convert back to color?
No. The color information is discarded. Keep your original if you might need it.
Will highlighted text still be visible?
It becomes a gray tint. Yellow highlighter converts to a very light gray and can be nearly invisible — check before sending.
Does this make text unselectable?
Yes. Pages are rebuilt as images, so the text is no longer selectable. If you need it to stay searchable, keep the original.
What people do around this step
Meeting an upload size limit
- Count pages in a PDFfind out what you're actually working with
- Remove pages from a PDFdrop pages the form never asked for
- Convert a PDF to grayscaleYou are here · strip the color, which is usually most of the weight
- Compress a PDF to 200KBsqueeze what's left down to the cap