Enter any colour to learn the closest named colour, the standard CSS name designers and developers use.
CSS defines 148 named colours, from the primaries down to very specific shades like papayawhip and mediumslateblue. Given any colour, the finder converts it to RGB and measures the distance to every named colour in that space (weighted slightly toward how human vision judges difference), then ranks the closest three. For most colours the winner is a genuinely useful name, the one a developer would type, while for unusual shades it honestly reports the distance so a near-name is not mistaken for an exact one.
Exact matches do happen when a colour is itself a named CSS colour, common with palette colours taken from web designs. Distance 0 means the hex is precisely that named colour.
Why is the nearest name still not quite the same colour? 148 names must cover 16.7 million colours, so most shades fall between names. The finder ranks honestly by distance rather than pretending a match is exact.
Are these the same names as paint colours? No, paint names are each manufacturer's own. These are the standard web/CSS colour names, which is what 'what color is this hex' usually asks.
What is a good distance? Under about 15 in the weighted metric, the name is visually almost identical. Over 60, treat it as 'in the family of' only.