Is there a new Mob damage calculator?

I'm looking for a calculator that will tell you how much damage a mob will do to you depending on various stats. Pretty much like the one in the known formulas thread. That one though seems to not work, as I've tested a bunch of values and they all seem to come out way wrong. I don't know if or when they changed how mobs dealt damage but an updated calc/formula would be greatly appreciated. Thanks.