Hex to HSV Converter
HSV is the model behind almost every color picker you have used, the square panel with the hue slider underneath. It shares hue with HSL but handles the other two axes differently, which is why the same color reports different numbers in each.
How the conversion works
Normalise the channels to 0–1. Value is simply the maximum channel. Saturation is the spread between maximum and minimum, divided by the maximum. Hue is calculated exactly as in HSL.