[RPG] How to calculate the BAB, CMB and CMD


I'm a new player and I don't know how to calculate some values on my character sheet, namely BAB, CMB and CMD.

They are a level 2 elven feral hunter with the following ability scores: Str 9, Dex 18, Con 11, Int 14, Wis 12, Cha 16.

They are wearing light armor and they carry either a compound longbow or just a longbow.

Best Answer

First of all, you need to understand that BAB (base attack bonus) is just a component of your attack bonus and that it will almost never be used alone.

BAB depends entirely on your level and class. Go look at the hunter class table and see what it tells you. It's +1.

To get your CMB you need to add up your BAB, your Str modifier and a modifier based on your size.

Elves are medium size and get no size modifier

An ability modifier is the value you get by subtracting 10 from your ability value, halving and rounding down. For strength 9 it's -1.

So, your CMB is +1 -1 +0 = +0

To get your CMD you need to add up your BAB, your Str modifier, your Dex modifier, a modifier based on your size. Several modifiers to your armor class (AC) are also comupted, but the Armor bonus (which depends on your actual, physical suit of armor) is not among them.

So, your CMD is +1 -1 +3 +0 = +3

It drops to +0 while you're flat footed, because you lose your Dex bonus to CMD if that condition applies.

Feats and other different things might add some bonuses to CMB or CMD (never to BAB) but they're usually very clear about it when they do. Read their descriptions carefully.