Reference

Actions, combat rules, conditions, skills, feats and languages. Search by name.

During play

Actions Every combat action and what it does: Attack, Dash, Disengage, Dodge and more.

Conditions Every condition and what it does to a creature

Combat Rules Cover, advantage and the core combat rules

For your character

Feats Character feats from every source, with their prerequisites.

Skills Skills and the abilities behind them

Optional Features Eldritch invocations, maneuvers, metamagic and fighting styles

Languages From Common to Abyssal, with their scripts

Deities Gods by pantheon, with alignment, cleric domains and symbol

Combat Rules

Armor Class

Source: XPHB

Armor Class (AC) represents how hard a creature or an object is to harm in combat. The higher a creature's AC, the harder it is to hit.

An attack roll that equals or exceeds a target's AC is a hit.

AC is calculated at the start of the game and normally doesn't change during a combat encounter, though various spells and features can adjust it temporarily.