Cover

Depending on battlefield positioning and conditions, characters may have cover from enemy attacks, or enemies may have cover from their attacks. Determining whether a target has cover is different depending on the type of attack. To determine whether a target has cover from a character’s ranged attack, choose a corner of the attacking character’s square. If any line from this corner to any corner of the target’s square passes through an object or border that would block line of effect, or through a square occupied by a hostile creature, the target has cover.
When making a melee attack against an adjacent target, the target has cover if any line, from any corner of the attacker’s square, to the target’s square goes through a wall (including a low wall) or some other blocking object. When making a melee attack against a target that isn’t adjacent to the attacker (such as with a reach weapon), use the rules for determining cover from ranged attacks.

Low Obstacles and Cover

A low obstacle (such as a wall no higher than half the character’s height) provides cover, but only to characters within 30 feet (6 squares) of it. The attacker can ignore the cover if they are closer to the obstacle than their target.

Cover and Attacks of Opportunity

Characters can not take an attack of opportunity against an opponent with full cover relative to them.

Cover and Body Saves

Half Cover or better grants a character advantage on Body saves against attacks that originate or burst out from a point on the other side of the cover from them. Note that spread and emanation effects can extend around corners and thus negate this cover bonus.

Cover and Stealth Checks

A character can use cover to make a Stealth check while benefiting from the cover. Without cover, the character typically needs concealment or some other ability to make a Stealth check.

Big Creatures and Cover

Characters have the ability to use creatures that are larger than them as soft cover. Any character with a space larger than 5 feet (1 square) determines cover against attacks slightly differently than smaller creatures do. Such a character can choose any square that they occupy to determine if a target has cover against their melee attacks. Similarly, when making an attack against such a target, the attacker can choose any of the squares the target occupies to determine if it has cover against them. Finally if a character is benefiting from cover granted by a large creature, any other creatures that are on the opposite side of the creature providing cover, in relation to the character, also have cover from the character.

Types of Cover

After determining whether or not a character has cover, it is then determined what type of cover the character has.

Partial Cover

If a character has cover, but more than half the character is visible, they gain a cover bonus equal to a +2 dodge bonus to AC and a +1 dodge bonus on Body saving throws, from area effects that are appropriate. This partial cover is subject to the GM‘s discretion.

Half Cover

If a character has half or more of their body obscured, but not by a hard object such as a wall, they are considered to have half cover. Half cover grants characters a +4 dodge bonus to AC. However, half cover provides no bonus on a Body save but does grant advantage on appropriate body saves, nor does half cover allow you to make a Stealth check.

Full Cover

In some cases, such as a character hiding behind an arrow slit, the character may gain the benefits of Full cover. Full cover grants a greater bonus to AC and Body saves. In such situations, the normal cover bonuses to AC are doubled (to +8). A character with this full cover ignores all effects on a successful save against an attack or ability in which the Body save bonus applies. Furthermore, full cover provides advantage on Stealth checks.

Total Cover

If a character does not have line of effect to their target (that is, they cannot draw any line from their square to their target’s square without crossing a solid barrier), they are considered to have total cover from the character. The character can not make any targeted attacks against a target that has total cover. However some blast and emanation effects can go around and bypass total cover if their area of effect is large enough (GM Discretion).