How to use
- Upload your image (JPG, PNG, WebP, or GIF).
- Choose a method — Luminance for a natural, perceptual black & white, or Average for a flatter look.
- Pick an output format (PNG and WebP keep transparency; JPG fills transparent areas with white).
- The preview updates instantly — click Download grayscale image to save it.
Luminance vs average
The human eye doesn’t see all colours as equally bright. Green looks much brighter than blue at the same intensity. The luminance method accounts for this using the Rec. 601 weights (0.299·R + 0.587·G + 0.114·B), so a red apple and a green leaf end up at believable, distinct shades of gray.
The average method just averages the three channels. It’s faster to reason about and gives a higher-contrast, slightly “flatter” feel — sometimes desirable for graphic or high-key looks.
Common use cases
- Printing photos in black & white to save colour ink.
- Design work — desaturating images for minimalist or monochrome layouts.
- Accessibility — checking that a UI still reads clearly without colour.
- Web placeholders — grayscale images compress smaller for thumbnails.
Private by design
Every pixel is converted locally in your browser via the Canvas API. Your image is never uploaded, so the conversion is instant and your files stay private.