Grayscale Image
Convert a colour image to black and white, with strength control.
Processed on your device — never uploaded
Uses the Rec. 601 luminance weighting (0.299R + 0.587G + 0.114B).
What Is This Tool?
This tool converts each pixel to grey using a perceptual luminance formula, so the result matches how bright each colour looks to the eye rather than a flat channel average. The strength slider lets you partially desaturate for a muted look instead of full black and white.
How It Works
Drop an image onto the box or select one.
Leave Grayscale % at 100 for full black and white.
Lower it for a partially desaturated effect.
Click Download PNG.
Everything runs locally in your browser — the image you choose is decoded onto an HTML canvas on your own device and is never uploaded to a server.
Features
- Perceptual luminance weighting
- Adjustable 0–100% strength
- Optional gentle contrast boost
- Keeps original resolution and transparency
- Client-side pixel processing
Common Use Cases
- Creating a mono version of a logo
- Giving a photo set a consistent editorial look
- Preparing an image for a grayscale print
- Reducing visual noise behind overlaid text
Frequently Asked Questions
Why not just average the R, G and B values?
A flat average makes greens too dark and blues too light compared with how we perceive them. The luminance weighting (about 30% red, 59% green, 11% blue) looks correct to the eye.
What does a value below 100% do?
It blends the grey result with the original colour, so 50% gives a desaturated, muted-colour image rather than pure grey.
Is the file smaller in grayscale?
Only slightly as a PNG, since it is still stored as RGB. Convert to JPEG or WebP afterwards for a real size drop.
Does it affect transparency?
No. Only the colour channels are changed; the alpha channel is left as-is.
Is my image uploaded?
No, the conversion is local.