AC Bonus

When unarmored and unencumbered, the monk adds his Charisma bonus (if any) to his AC and CMD. In addition, at level 4 a monk gains a +1 bonus to AC and CMD. This bonus increases by 1 for every four monk levels thereafter, up to a maximum of +5 at 20th level. These bonuses to AC apply even against touch attacks or when the monk is flat-footed. He loses these bonuses when he is immobilized or helpless, when he wears any armor, when he carries a shield, or when he carries a medium or heavy load. If a different class ability, like shifter's Defensive Instinct or barbarian's Cunning Elusion, also allows the character to add his Wisdom bonus to AC and CMD, these two bonuses cannot be applied simultaneously: the monk's class ability suppresses the others.