How does critical strike chance stack?

Question

I was wondering how critical strike chance stacks? Say I buy a Phanton Dancer with its 30% crit chance. Now if I buy another Phanton Dancer, what is my critical chance?

Answer 1

they stack additively, so just add up the crit chance. 1 PD will increase your total crit chance by +30%. The 2nd PD will increase your total crit chance by +30%, so +60% crit chance total from 2 PD's.

Answer 2

Crit chance caps out at 100% where your basic attacks are just crits. These are other things that stack additively

Ability power Armor, Armor penetration, Armor reduction, Attack damage, Attack speed , Cooldown reduction, Critical strike chance, Critical strike damage, Health, Health regeneration, Life steal, Magic penetration, Magic resistance, Magic resistance reduction, Mana, Mana regeneration, and Spell vamp

Source: http://leagueoflegends.wikia.com/wiki/Stacking