Crit chance formula is (crit rate - crit resist) * 42 / player level
An example of this is:
(100 - 433) * 42/280 = C
This will be 0%, but with sneak hit active it gives a +70% crit chance so the end result is 70% crit chance.
There is also the more recent innovation to this formula which is:
C = (((crit rate - crit resist) * X) + skill crit chance)
Where X = 42 / player level ; [0,1]
(In case you don’t know what the brackets mean… They just mean that 42 / level can only be a value between 0 and 1. Also any value above 1 is reverted to 1 for this specific case).
An example using this newer version would be like this:
(100 - 433) * 42 / 280 + 70% = C
(c.rate - c.resist) * 42/level + sneak hit 5 = C
-333 * 0.15 + 70% = C
-50% + 70% = C
30% = C
So, it’s 30% crit chance…
The first formula is generally accepted. The second one still needs more proof.