Cycles Principled V Glossy

As I’ve either re-visited projects or continued working on those started before the principled shader, I’ve taken the opportunity to convert materials.

Does the principled glossy work differently than the standalone glossy shader? I can’t take the value from a glossy node to principled and get the same result, and in fact I have to add a lot more roughness to principled to match.

Now I know that the glossy had issues with roughness not being a linear value, so I’m assuming that this has been addressed in the principled shader, in which case, what’s the math to convert between the two?

hope this helps

Awesome. Square root. Much better than eyeballing.

Thank you.