Base Attack Bonus

The Base Attack Bonus (or BAB) is a number that represents a character or monster's skill at fighting that comes purely from his or her profession, training, and personal experience. BAB is an important part of your total attack bonus. It also affects your attack speed.

Benefits
Base Attack Bonus serves several roles in DDO:
 * It is added to all attack rolls with any weapon, including bare hands.
 * It determines the number of attacks in your attack sequence.
 * It determines player attack speed:
 * For melee weapons, attack speed increases at BAB 1, 3, 5, 10, 15, 20, and 25
 * For bows and thrown, attack speed increases with each point of BAB, and it grows much faster than for melee.
 * BaB above 25 does not increase attack speed. 25, 26, 27, 28, 29, and 30 BaB have the same attack speed for all animation styles.


 * Several combat-related feats require a minimum BAB to unlock.
 * The Physical Resistance Rating that you receive for wearing armor scales with BAB.

Progression
The BAB progression for players is based on their class (for creatures, on their HD), and follows one of the three following progressions:
 * +1 BAB per level, the best BAB progression, is reserved for the warrior classes (Barbarian, Fighter, Paladin, and Ranger).
 * +.75 BAB per level, the second best BAB progression, is used by the Alchemist, Artificer, Bard, Cleric, Druid, Favored Soul, Monk, Rogue and Warlock.
 * +.5 BAB per level, the worst BAB progression, is used by the Sorcerer and the Wizard. Epic levels also use this progression.

Fractions are dropped (rounded down). To calculate BAB of a multiclass character, first round down the BAB for each class, then add numbers together. For example, a level 3 character with one level of rogue, one level of bard, and one level of sorcerer has a BAB of 0 (floor(0.5) + floor(0.75) + floor(0.75)). A level 9 character with 1 rogue and 8 barbarian levels has a BAB of 8 (8 + floor(0.75)).

Multiple Numbers on Class Pages
The BAB column on class spreadsheets indicate multiple numbers. The first number listed is the Base Attack Bonus. Subsequent numbers indicate the attack bonus the character achieves on various stages of their attack sequence.

Increasing base attack bonus
Certain spells and abilities make your base attack bonus equal to character level:
 * Bladesworn Transformation
 * Divine Power spell
 * Divine Power toggle: Warpriest enhancements T5 ability
 * Past Life: Student of the Sword clicky
 * Tenser's Transformation spell
 * Knight's Transformation toggle: Eldritch Knight enhancements T4 ability
 * Victory Song toggle: Warchanter enhancements level 18 core ability
 * Ultimate Enlightenment: capstone of Enlightened Spirit enhancements
 * Just Cause: Divine Crusader first innate ability
 * More Hidden Blades Orichidium Reaction Vile Chemist enhancements Core 4 ability

Additionally, Flurry of Blows allows a centered monk to receive a full BAB progression for all monk levels, rather than the standard 0.75.

Note: These abilities increase the BAB granted by All levels to 1, including Epic Levels, allowing characters to reach 30 BAB at level 30, which is otherwise impossible, even on pure classes such as Barbarian, Fighter, or Ranger.