Armor Class

The Armor Class represents the ability to not get hit in a way that causes damage. This can be imagined by dodging attacks, wearing actual armor and by magical and several other effects. The AC does not reduce damage in any way when a character gets hit successfully. It is only affecting the chance of an attack to be a successful hit or not. The amount of damage taken by a successful hit can only be reduced by resistances.

Armor Class Composition
A character's or creature's AC is equal to the following:

10 + Size Modifier + Armor Bonus + Shield Bonus + Dexterity Bonus + ( Deflection Bonus + Natural Armor + Dodge Bonus + modifiers from feats, abilities and conditions)


 * Size Modifiers follow a simple rule; smaller things are harder to hit than bigger things: Colossal –8, Gargantuan –4, Huge –2, Large –1, Medium +0 (all playable races but halflings and gnomes), Small +1 (halflings and gnomes), Tiny +2, Diminutive +4, Fine +8.


 * Armor Bonus comes usually from the armor that is equipped


 * Shield Bonus comes usually from a shield that is equipped


 * Dexterity Bonus is defined by the Attribute Dexterity. The Dexterity Bonus is limited by the type of armor that is worn.


 * Deflection Bonus, Natural Armor, Dodge, Circumstance and Insight Bonuses are sometimes granted by Feats, magical items or spells. Creatures often have Natural Armor in the form of thick skin or scales.

Stacking of AC bonuses
If a character is affected by multiple items, spells or other sources that grant the same kind of AC bonus, the effects DO NOT STACK. The only exception of this are Dodge Bonuses which add up when they are granted from multiple sources. But, for example, if you are wearing armor and use the spell "Mage Armor" (that also grants AC as Armor Bonus), only the higher bonus of the two is applied.

Different Types of AC
Depending on the situation not all AC modifiers in the equation above are applied.

Flat Footed AC

In certain situations you can't see an attack coming or you are prevented from reacting to it. This is first and foremost the case when combat begins and a character has not acted yet du to his Initiative. In this case the Dexterity Bonus and the Dodge Bonus are not added to your AC. More detailed information about being Flat-Footed can be found → here ←.

Touch AC

Some attacks hurt you in a way that armor, shields and tough skin can't prevent, thus Armor Bonus, Shield Bonus and Natural Armor are not added to your AC. The enemy merely has to touch you without having to find a weak spot to hit. This is the case for many magical attacks.