It is not called cowering behind a wall!
|Degree of Cover||Cover Bonus to AC||Cover Bonus to Reflex Saves|
|1/4 (Standing behind a 3ft tall wall)||+2||+1|
|1/2 (Fighting around a corner, or standing at a window)||+4||+2|
|3/4 (Peering around a corner or out a window)||+7||+3|
|9/10 (Peering through an arrow slit, or through a mostly closed door)||+10||+4|
|Total Cover (Completely behind a wall)||-||-|
A character with 9/10 cover take half damage on a failed reflex save, and none on a successful save. This does not stack with the effects of Evasion or Improved Evasion, as these feats designate a character’s ability to instinctively find better cover.
In addition, a character benefiting from 3/4 cover receives a +5 cover bonus to hide. A character benefiting from 9/10 cover receives a +10 cover bonus to hide.
A character benefiting from total cover can not be targeted and automatically succeeds at reflex saves.
To gain a cover bonus on a reflex save, the effect’s point of origin must be on the other side of the cover.
A called shot generally ignores cover bonuses to AC if the targeted body part is not behind cover. See Called Shots.