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, 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 you can make: in DDO you gain your second attack at +1 BAB, your third attack at +5 BAB, and your fourth attack at +10. The 3rd attack gets a +5 bonus to hit, and the 4th attack gets a +10 bonus to hit (currently, the 4th attack also doubles the threat range, but developers have stated this would be removed in the August 2006 update).

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