Convert red, green and blue channels into hue, saturation and lightness, the form that says what a colour actually is.
Three channel numbers tell you how a screen makes a colour, not what the colour is. rgb(74 124 47) means nothing at a glance; the same colour as hsl(96 45% 34%) reads immediately as a dark, medium-saturated green. This conversion is what colour pickers do internally when you drag a hue slider.
L = (max + min) / 2, S = (max − L) / min(L, 1 − L), H from the winning channel × 60°
The channels are first scaled to 0..1. Lightness is the midpoint of the largest and smallest, saturation measures their spread relative to how much room that lightness leaves, and hue is found from which channel is largest and how far the other two trail behind.
A number that disagrees with its source is a defect, not a rounding preference.
What did you enter, what did the tool show, and what did you expect instead? If you have a source that disagrees with ours, a link to it is the most useful thing you can send.
Opens your mail app with the page and tool already filled in.
Convert hue, saturation and lightness into the red, green and blue channels a screen actually uses.
Turn red, green and blue channel values into the hex code stylesheets expect, with alpha where you need it.
Convert a hex colour into hue, saturation and lightness — the form that makes a colour easy to lighten, darken or desaturate by hand.