A creature’s Armor Class represents how well the creature avoids being wounded in combat. The AC of a character is determined at character creation (see “Character Creation”), whereas the AC of a monster appears in its stat block. Calculating AC. All creatures start with the same base AC calculation: Base AC

10 + the creature’s Dexterity modifier A creature’s AC can then be modified by armor, magic items, spells, and more. Only One Base AC. Some spells and class features give characters a different way to calculate their AC. A character with multiple features that give different ways to calculate AC must choose which one to use; only one base calculation can be in effect for a creature.