Calculating the AC of a character involves adding up the various sources of AC. Most of these sources do not stack, with the exception of Dodge AC. For more information Armor Class.
There are six types of AC in NWN2: Armor, Deflection, Dodge, Natural, Shield and Untyped. And each subtype, other than untyped, can be a base bonus or an enhancement bonus. Base bonuses stack and tend to be granted by persistent feats, while enchancement bonuses do not stack (with the exception of Dodge which stacks to +20) and are granted by spells, equipment and spell-like feats.
Against regular attacks all the types of AC are used for defense. Against touch attacks Deflection, Dodge and Untyped are used for defense. When caught flat footed, Armor, Deflection, Natural and Untyped are used for defense.
Untyped
- Every creature has a base 10 points of untyped AC.
Feats
- A monk's AC bonus, Wisdom Bonus and +1 per 5 levels.
- Sacred Fist AC bonus: 1 at 1, 2 at 5, 3 at 10.
- Small stature: +1
- Combat Expertise: +3
- Improved Combat Expertise: +6
Armor
Base
Items
- Padded armor: +1
- Leather armor: +2
- Studded leather armor: +3
- Hide armor: +3
- Chain shirt: +4
- Scale mail: +4
- Chainmail: +5
- Breastplate: +5
- Splint mail: +6
- Banded mail: +6
- Half plate: +7
- Full plate: +8
Enhancement
Items
- Armor: +0-20
- Bracers: +0-20
Spells
- Improved Mage Armor: +6 AC ( nw_s0_impmagarm.NSS )
- Mage Armor: +4 AC ( nw_s0_magearm.NSS )
- Magic Vestments: +1/4 caster levels (max +5)
Shield
Base
Items
- Light Shield: +1
- Heavy Shield: +2
- Tower Shield: +4
Feats
- Two-Weapon Defense: +1 AC Shield Bonus
- Improved Two-Weapon Defense: +2 AC Shield Bonus (Replaces the bonus from Two-Weapon Defense)
Enhancement
Items
- Shield: +0-20
Spells
- Shield: +4 Shield
- Shades: +4 Shield ( nw_s0_shadescaster.NSS )
- Magic Vestments: +1/4 caster levels (max +5)
Natural
Base
Feats
- Armor Skin: +1
- Bone Skin: +2+2 every four Pale Master levels
- Red Dragon Disciple AC bonus: +1 with an additional +1 bonus gained at level 4 and every 3 subsequent Red Dragon Disciple levels.
- Yuan-Ti Pureblood AC bonus: +1 racial bonus
Enhancement
Items
- Amulet: +0-20
Spells
- Righteous Might: +2 Natural ( nw_s0_rightmight.NSS )
- Shadow Shield: +5
- Tortoise Shell: Max 9 or ( 6 + ( Level - 11) / 3) whichever is higher ( nw_s0_tortshell.NSS )
- Spiderskin: Max +5
- Barkskin: Max +5
Feats
- Elephant's Hide: +7
- Barbarian Rage with Ice Troll Berserker Feat: +2 to +6 (see nw_s1_barbrage.NSS)
Deflection
Enhancement
Items
- Rings: +0-20
- Cloaks: +0-20
- Helms: +0-20
- Belts: +0-20
- Weapons: +0-20
Spells
- Protection from Alignment: +2 Deflection (Vs. Target Alignment)
- Shield Other: +1 AC for protected person
- Shield of Faith: +2 with a an additional +1 bonus for every 6 caster levels (+5 max).
- Aura versus Alignment: +4 (Vs. Target Alignment) [for the function doAura in x0_i0_spells.nss]
Feats
- Blessing of the Spirits: Spirit Shaman 4 on self, +2
- Warding of the Spirits: Spirit Shaman 10 on Party, +2
Dodge
Base
Abilities
- Dexterity bonus to AC: Dexterity modifier to a maximum of the Maximum dexterity bonus granted by armor. Technically this is not dodge AC, but since Uncanny Dodge does not work and the Dexterity bonus is lost and applied whenever a dodge bonus is lost or applied it might as well be grouped with them.
Feats
- Slippery Defense: +4 AC bonus
- Improved Defense: +1 with an additional +1 bonus gained at level 4 and every 3 subsequent Dwarven Defender levels.
- Dodge: +1 AC
- Swashbuckler Dodge: +1/5 Swashbuckler levels.
- Luck of Heroes: +1
- Canny Defense: Intelligence modifier up to Duelist level (does not stack with Unfettered Defense)
- Unfettered Defense: Intelligence modifier up to Invisible Blade level (does not stack with Canny Defense)
Skills
- Tumble: Up to +1 per 10 base ranks
Enhancement
Items
- Boots: +0-20
Spells
- Enlarge Person: -1 ( nw_s0_enlrgeper.NSS )
- Righteous Might: -1 ( nw_s0_rightmight.NSS )
- Recitation: +2, +3 if same deity ( nx_s0_recitation.NSS )
- Reduce Person: +1
- Haste: +1
- Battletide: +1
Feats
- Barbarian Rage: -2
- Frenzy: -4 ( nw_s1_frenzy.NSS )
- Defensive Stance: Dwarven Defender +4
- Divine Shield: Charisma modifier
Songs
- Chorus of Heroism: +4 for party
- Inspire Defense: After level 10, ( 2 + ((Level - 5) / 5) ( nw_s2_sngindefn.NSS )