How Armor Class Works in D&D 5e (And How to Raise Yours)

26 March 2026

Armor Class (AC) is the number an attacker needs to match or beat to hit you. It’s one of the most important numbers on your character sheet — and unlike hit points, you don’t have to track it as it changes. It’s a fixed value unless something specifically modifies it.

The baseline: unarmored

If you’re wearing no armor, your base AC is 10 + your Dexterity modifier. This is the default for everyone not wearing armor. A character with 16 Dexterity (+3) and no armor has AC 13.

Armor types

The PHB divides armor into three categories: light, medium, and heavy. Each has different rules for how Dexterity applies.

Light armor

Light armor adds your full Dexterity modifier. A Rogue or Ranger with high Dexterity typically uses studded leather for maximum AC.

Wearing light or medium armor requires at least 1 hour to don (put on) fully. Light armor can be donned in 1 minute.

Medium armor

Medium armor caps Dexterity at +2 — so having 20 Dexterity doesn’t help beyond that. A character with 14+ Dexterity (+2 cap) gets full benefit from medium armor. Anything higher is wasted for AC purposes.

Heavy armor

Heavy armor ignores Dexterity entirely. It also requires a minimum Strength score to wear without movement penalties. Most heavy armor imposes disadvantage on Stealth checks.

Heavy armor must be donned carefully — plate armor takes 10 minutes to don fully.

Shields

A shield is a bonus +2 AC while held. Any class that can use a shield can hold one. Shields require one hand, so you can’t use a two-handed weapon or hold a weapon in both hands while using one.

Plate + shield = AC 20. This is the highest unmagical baseline in the game.

Armor proficiency

Wearing armor you’re not proficient with imposes serious penalties: disadvantage on ability checks, saving throws, and attack rolls involving Strength or Dexterity, and inability to cast spells.

Who can wear what:

• Wizards and Sorcerers: No armor proficiency. They rely on Mage Armor, Unarmored Defense, or other features.
• Rogues, Rangers, Bards: Light and medium armor.
• Clerics, Druids, Warlocks: Light and medium armor by default (some subclasses get more).
• Fighters, Paladins, Barbarians: All armor types.

Special unarmored defense options

Some classes don’t wear traditional armor but have superior unarmored options:

Barbarian – Unarmored Defense: AC = 10 + Dexterity modifier + Constitution modifier. A Barbarian with 16 Dex and 18 Con has AC 17 without a single piece of armor.

Monk – Unarmored Defense: AC = 10 + Dexterity modifier + Wisdom modifier. They also can’t benefit from a shield with this feature.

Sorcerer/Wizard – Mage Armor (spell): AC becomes 13 + Dexterity modifier for the duration (8 hours). A Sorcerer with 16 Dex has AC 16 with this spell active.

How to raise your AC

Prioritise the right stat. Dexterity raises AC in light and medium armor. Constitution matters for Barbarian unarmored defense.

Upgrade your armor. Going from leather (11 + Dex) to studded leather (12 + Dex) is a cheap early improvement.

Use a shield if your class and build allow it.

Magic items. A +1, +2, or +3 shield or armor adds to AC. A Ring of Protection adds +1.

Spells and features: Shield of Faith adds +2 AC. The Shield spell (reaction) adds +5 AC until the start of your next turn. The Cleric’s Shield spell is one of the strongest defensive reactions in the game for casters.

AC in combat: a practical note

AC only matters for attack rolls. It has no effect on saving throws (those use your saving throw bonuses, not AC), and it doesn’t reduce damage when you are hit. A fireball that forces a Dexterity saving throw doesn’t care about your AC at all.

High AC makes you hard to hit with weapons and attack-roll spells. High saving throw bonuses protect you from everything else. You want both — but if you must choose, most DMs agree that surviving the first round matters more than anything else.