Convert an image to grayscale
Converts to grayscale using perceptual luminance weights rather than a naive channel average, so the result matches how the eye actually reads brightness.
Drop an image here
or , or press ⌘V to paste
Processed on your device. Nothing is uploaded.
How to use it
- Drop an image in.
- Download the grayscale version.
Questions
Are my images uploaded anywhere?
No. Everything runs in your browser using the Canvas API — the file never leaves your machine, and the tool keeps working if you go offline after the page loads. There is no account, no queue, and no server-side copy to delete later.
Why not just average the red, green and blue?
Because the eye is far more sensitive to green than to blue. A flat average makes greens look too dark and blues too light. This tool uses the standard luminance weights (0.2126 R, 0.7152 G, 0.0722 B), which is what image software and the WCAG contrast formula both use.
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- Image cropperCrop an image by dragging, with optional aspect-ratio locking for 1:1, 4:3, 16:9 and 9:16. Free and private.
This is one keystroke inside LayerShot
The desktop app captures the screen, applies your styling and puts the result on your clipboard without a browser tab, an upload, or a download folder full of files called Screenshot (3).png. One payment, one Mac and one Windows PC, lifetime updates.