Do you need a NCOL code instead of HWB?
Dopely's Converter can do it for you.
The easiest and fastest way to get NCol values equivalent to the HWB values on the css4 page is to use this tool. No wasting time!
This color model is very similar to HSL. HWB refers to Hue, Whiteness and Blackness. You can adjust the white and black values of each color with this model. This color model is commonly used in css4.