[RPG] How to calculate the attack bonus(es) for Flurry of Blows


Being fairly new I'm a little lost on the math for this. I read that there is a -2 on attack rolls in the description of "Flurry of Blows". Then in the chart I see FoB has its own attack bonus (+1/+1 at level 3). Then there is the base attack bonus (+2 at level 3). Then the STR bonus. Do all these add up or does the FoB attack bonus replace the BAB for this attack?

Sorry if the question sounds stupid. I'm still learning and the books are not quite clear.

Best Answer

The formula for a melee attack roll is usually:

BAB + Str Mod + 1d20

Flurry of Blows makes two changes to this formula:

When doing so, he may make one additional attack, taking a –2 penalty on all of his attack rolls, as if using the Two-Weapon Fighting feat. These attacks can be any combination of unarmed strikes and attacks with a monk special weapon (he does not need to use two weapons to utilize this ability).


For the purpose of these attacks, the monk's base attack bonus from his monk class levels is equal to his monk level.

This makes the attack formula:

Monk Level + Str Mod - 2 + 1d20

The class table combines Monk Level and the -2 penalty into the column Flurry of Blows Attack Bonus. Giving you the formula:

Flurry of Blows Attack Bonus + Str Mod + 1d20