Turn any color into a perceptually correct gray
This converter reduces a color to a single gray level the way the human eye perceives its brightness. It is what you want for desaturating a swatch, checking how a color reads in grayscale, or generating a neutral tone from a brand color.
How it works
A naive grayscale just averages red, green, and blue. The problem is that the eye does not weight those channels equally — green contributes far more to perceived brightness than blue does. The classic fix is the ITU-R BT.601 luma formula:
gray = 0.299 * R + 0.587 * G + 0.114 * BThe weighted sum produces one number, which is then placed in all three channels to make a neutral gray. The tool rounds to the nearest integer and shows the result as both an rgb() triple and a hex code. For comparison it also reports the BT.709 weighting (0.2126 * R + 0.7152 * G + 0.0722 * B), the standard used for HD video and sRGB, which leans even more heavily on green.
Notes and example
A vivid orange #e67e22 (rgb(230, 126, 34)) converts under BT.601 to about 137, giving the gray #898989 — a medium tone, because orange is moderately bright to the eye. Pure green converts to a much lighter gray than pure blue of the same intensity, which is exactly the perceptual effect the weights are designed to capture. The side-by-side swatches let you confirm the gray reads at the brightness you expect.