Convert an image to grayscale
Remove colour from a photo using true luminance weighting, not a flat average.
Remove colour from a photo using proper luminance weighting — 21% red, 72% green, 7% blue — rather than a flat average that leaves skies and skin tones looking wrong.
Processed in your browser
Drop your image here
or choose an image from your device
Accepts JPG, PNG or WEBP · No fixed size limit — we adapt to what your device can handle. Very large files may take longer or show a warning.
About Grayscale Image
Why weighting matters
The human eye is far more sensitive to green light than to red or blue. A naive average of the three channels makes reds and blues look unnaturally bright and greens too dark. Rec. 709 luminance weighting matches how brightness is actually perceived, so tonal relationships in the photo stay believable.
What stays and what changes
Only the colour values are recomputed — pixel dimensions and any transparency (for PNG and WEBP sources) are left untouched. The output is still saved as a normal colour-capable file, just with every pixel's red, green and blue values now equal.
Settings and output
No adjustable controls
This tool applies one fixed, well-tested conversion. If you need a stylised tint or partial desaturation with a live preview, that's outside its scope by design — it does one thing reliably.
When to use it
- Producing a black-and-white version of a photo for print or a stylistic edit.
- Preparing a scanned document or ID photo that needs a neutral, colour-free look.
- Testing composition and contrast without colour as a distraction.
Limitations to know
- This produces a neutral greyscale look only — there's no sepia, duotone or custom tint option.
- The file is still stored as a colour-capable format (JPG, PNG or WEBP), not a true single-channel greyscale file.
- Grayscale conversion is one-way; the original colour data isn't kept in the output.
Common problems and fixes
Why does my grayscale image look different from a plain 'desaturate' in another app?
Many simple tools average red, green and blue equally, which makes greens too dark and blues too bright. This tool uses perceptual luminance weighting instead, which usually looks more natural.
Did my transparent background survive?
Yes, for PNG and WEBP sources — only colour values change, the alpha channel is untouched.
The file size barely changed.
Removing colour variation helps a little, but the image is still saved in a full colour-capable format rather than a true single-channel file, so don't expect a dramatic size drop from grayscale alone.
How to use it
- 1Drop a JPG, PNG or WEBP photo into the upload area.
- 2Press Convert. Each pixel is recomputed with Rec. 709 luminance weighting — 21% red, 72% green, 7% blue — rather than a flat average of the three channels.
- 3Compare the preview: skies and skin tones keep sensible brightness relationships instead of going muddy.
- 4Download the black-and-white file in the same format you uploaded.
Frequently asked questions
Why use luminance weighting instead of averaging R, G and B?
The eye is far more sensitive to green than to blue. A flat average makes red and blue areas look unnaturally bright and green foliage too dark; Rec. 709 weighting matches perceived brightness.
Will the grayscale file be smaller?
Usually a little, because the colour channels now carry no variation, but the file is still saved as a normal colour-capable JPG, PNG or WEBP rather than a true single-channel greyscale image.
Is transparency preserved?
Yes for PNG and WEBP — only the colour values change, the alpha channel is left alone.
Can I get a sepia or duotone look instead?
Not here. This tool does one thing: neutral greyscale. Tinting would need colour controls that would make the result unpredictable without a live preview.
Can I undo the grayscale conversion afterwards?
No — once colour data is discarded and the file is re-encoded, there is no colour information left to restore. Keep your original file if you might need colour again.
Will grayscale conversion help an image print in black and white?
It helps you preview the exact tones a printer will produce, since some printers convert colour photos to grayscale differently. Converting here first also confirms contrast looks right before you commit paper and ink.
Does this work on a screenshot with UI colours?
Yes, the same luminance weighting is applied to every pixel regardless of content, though flat UI colours can end up closer together in brightness than photographic tones, reducing contrast between elements.
Related guides
- JPG vs PNG: which one should you actually use?One throws away detail to stay small, the other keeps every pixel and every transparent edge. Here is how to pick without guessing.
- How to reduce image file size without wrecking the pictureMost oversized images are oversized for one boring reason: the dimensions are far larger than anywhere they're displayed. Fix that first, then compress.
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