# How do I calculate my 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.

• Have you tried looking up the definitions for those things? They include formulas that explain how they are calculated. Do you have questions about those formulas or definitions? The more specific you are, the more helpful an answer is likely to be. – KRyan Feb 11 '18 at 20:58
• And, for that matter, we need more details to even just calculate this for you, for example the feats you have. – KRyan Feb 11 '18 at 21:14

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.

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.

For a single-classed character, BAB is just what it says at your level on the table for your class. Since feral hunter is a hunter archetype, you just look BAB up in Table: Hunter, where you’ll see an entry of +1. Your BAB is thus +1. Almost nothing in the game changes your BAB for any reason.1

The rules for combat maneuvers explain how to calculate your combat maneuver bonus as well as combat maneuver defense. Unless a feat or class feature or something changes things (and some do), the formulas are

\begin{align} CMB &= BAB + Str + m_{size} \\ CMD &= 10 + BAB + Str + Dex + m_{size} + m_{misc} \end{align}

where $BAB$ is your base attack bonus, $Str$ and $Dex$ are your Strength and Dexterity modifiers, respectively, and $m_{size}$ is the special size modifier that doesn’t matter ($m_{size} = +0$) for a Medium-sized creature like an elf. $m_{misc}$ is a any other modifiers you may have; I don’t know why they mention it for CMD and not for CMB, but you can have other modifiers to either. You haven’t mentioned anything that would give you such a modifier, though. Your animal focus class feature, though, could increase your Strength or Dexterity, increasing those parts of the calculation.

So for you, we have

\begin{align} BAB &= +1 \\ {Str}^2 &= -1 \\ {Dex}^3 &= +4 \\ m_{size} &= +0 \\ m_{misc} &= +0 \\ CMB &= +1 -1 +0 &= +0 \\ CMD &= 10 +1 -1 +4 +0 + 0 &= 14 \end{align}

Note that your choice of armor or weapon has absolutely no effect whatsoever on any of these calculations. Even your armor’s maximum Dexterity bonus only limits how much Dex you can put towards AC; it does not affect your Dex for the purposes of CMD.

1. To my knowledge, the divine power spell is literally the only exception. Hunters don’t get that spell, and no one gets it at 2nd level.

2. Assuming that you are not using the bull animal focus at the time.

3. Assuming that you are not using the tiger animal focus at the time.