Base Attack Bonus

The Base attack bonus (or BAB) is a number that represents your skill with a weapon.

The BAB progression for players is based on their class (for creatures, on their HD), and follows one of the three following progressions:
 * The best is +1 per level, which is reserved for the warrior classes (Fighter, Paladin, Ranger, and Barbarian), who start at +1 BAB.
 * The next best is +3/4 per level which is used by the Bard, Cleric, Monk, and Rogue, who start at 0 BAB.
 * The worst BAB progression +1/2 per level is used by the Sorcerer and the Wizard, who start at 0 BAB.

Base attack bonuses gained from different classes, such as when a character is a multiclass character, stack.

The Base Attack Bonus also determines the number of attacks in your combo cycle: in DDO you gain your third attack at +1 BAB and your fourth attack at +3. The third attack gets a +5 bonus to hit, and the fourth attack gets a +10 bonus to hit over the character's BAB.

For more details on the number of attacks and corresponding bonuses as the BAB increases, refer to the combo chain page.