Skip to content

Armor Class

Armor Class (AC) is the protective rating of a type of armor. Armor reduces the chance a character is attacked successfully — it prevents damage, not absorbs it. Damaging a Fighter in full plate mail is no small task.

The scale

AC runs on an inverted scale:

  • 10 is the worst (no armor).
  • 0 is the threshold for THAC0 calculations.
  • Below 0 is better armor. AC below –10 occurs only with very powerful magical armor.
  • Lower is better.

What modifies AC

  • Armor and shields — the base AC, plus magical bonuses (a chain mail +1 reduces your AC by 1 from base).
  • Dexterity — high Dexterity gives an AC bonus. See Ability Scores → Dexterity.
  • Spells — Armor, Shield, Stoneskin, etc.
  • Magical items — rings of protection, cloaks of protection, amulets, gauntlets.
  • Fighting styles — Single-Weapon Style grants +1/+2 AC; Sword and Shield Style grants +2/+4 AC against missiles. See Proficiencies.
  • Race / class abilities — Monks gain +1 AC every 2 levels; Kensais get +2 AC innately; Dragon Disciples gain +1 AC at several levels.

Stacking restrictions

You may not equip multiple magic items providing a similar bonus — for example, two rings of protection or a ring of protection paired with magical armor.

Source: iwdee/original_manuals/IWDEE - Mastering Melee & Magic.pdf — "Armor Class".