Online Tool Store
Grayscale Converter
Convert a photo to grayscale using a luminance-weighted or simple average method, with a side-by-side preview, in your browser.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Original
Grayscale
How the grayscale converter works
- Choose a photo and pick a conversion method.
- The tool reads every pixel's red, green, and blue values and replaces them with a single gray value.
- Download the result as a PNG once you're happy with it.
The formula
luminance-weighted gray = 0.2126×R + 0.7152×G + 0.0722×B
These specific weights come from the ITU-R BT.709 standard used for HDTV luma calculation, reflecting how much each color channel contributes to perceived brightness. Simple average instead uses (R + G + B) ÷ 3 for each pixel.
FAQ
What's the difference between the two methods?
Luminance-weighted grayscale accounts for how the human eye perceives brightness differently across red, green, and blue — it weighs green most heavily, since we're most sensitive to it, producing a more natural-looking result. Simple average just averages the three channels equally, which tends to look flatter.
Does this affect transparency?
No — only the red, green, and blue channels are converted to gray. The alpha (transparency) channel is left untouched, so transparent areas stay transparent.
Can I convert back to color afterward?
No — converting to grayscale discards the original color information permanently. Keep your original file if you might want the color version again later.
Is my image uploaded anywhere?
No. The conversion happens entirely in your browser using an HTML canvas — nothing is sent to Online Tool Store or any other server.
How we compare
| Feature | Online Tool Store | iLoveIMG grayscale | Photoshop desaturate |
|---|---|---|---|
| Choice of grayscale method | ✓ | Fixed method | ✓ |
| No install required | ✓ | ✓ | Desktop app install |
| Image never uploaded to a server | ✓ | Uploads to server | ✓ |
For a quick, private black-and-white conversion with a choice of method, the Online Tool Store Grayscale Converter does it right in your browser.