An armor bonus adds a variety of effects to a character's armor including: additional energy, additional energy recovery, additional health, a reduction in physical damage, and an increase in armor rating. Basic armor bonuses differ depending on a character's profession. Additional armor bonuses are available through the use of insignias and runes.
 Basic armor
Every armor piece in the game has basic stats that provides extra energy, energy recovery, health or armor depending on profession (but not including attributes from headgear). The bonuses gained from basic armor also depend on the armor piece (for instance for some professions armor for the legs and feet provide energy recovery).
 Attribute bonuses
Most headgear has a bonus of +1 to a single attribute. This "attribute headgear" is available for all attributes, although characters can only obtain attribute headgear for their primary profession's attributes. Attribute headgear generally has a name corresponding to its art style, although Elementalist and Paragon headgear has a name corresponding to its attribute and its corresponding art style. Some headgear common to all professions, such as the Norn Woad and the Dread Mask have a "Item attribute +1" bonus, which adds +1 to the respective rune attached to it
See attribute bonus for more information.
 Prefix bonuses
Except for maximum armor rating collector pieces and most festival headgear, all other armor has an insignia slot which allows the armor to be upgraded with an insignia. See Insignia for more information.
 Suffix bonuses
Armor can be upgraded with runes to add a suffix bonus. See Rune for more information.
- In the past all armor bonus prefixes were inherent. Prophecies armor art types had a specific inherent bonuses. For example, Warrior Templar armor was only available with Knight's Insignia (and named Knight's armor). Factions prefix bonuses were independent of armor art. Each art type was available with every inherent bonus for that profession. Nightfall armor introduced insignias. With the release of Nightfall, PvP armor also switched to using insignias. In the Thursday, May 24, 2007 update, all armor was adapted to Nightfall's insignia system and as such made all bonus independent of armor skin.