What is the relationship between Photoshop's leading and line-height in css?

Question

css

And if there is a connection, then how to calculate the line-height based on the leading.

Answer 1

I mean, what's the connection? They are the same, equivalent concepts.
Although there is a slight difference - in css you can specify line-height in both absolute (20px) and relative units (1.25). In Photoshop, only absolute (px, pt).
But essentially it's the same thing.
Just leading - a semi-slang, historical name, which was formed from lead - lead. It may be unfamiliar to people not from the typographical environment, so in css it was called more straightforward.