What armor class is
Armor class (AC) is a number that tells you how hard your character is to hit with an attack. When a creature attacks you, it rolls a twenty-sided die, adds its bonuses, and compares the total to your AC. If the total meets or beats your AC, the attack hits. A higher AC means fewer hits. If you need a refresher on the dice, see what dice are used in D&D.
How to calculate your AC
Your AC depends on what you wear and your Dexterity modifier:
- No armor: 10 + your Dexterity modifier.
- Light armor: the armor’s base AC + your full Dexterity modifier.
- Medium armor: the armor’s base AC + your Dexterity modifier, but the Dexterity bonus is capped at +2.
- Heavy armor: the armor’s fixed AC, with no Dexterity modifier added.
- Shield: +2 to AC while you carry it.
Only one suit of armor counts at a time, and you can use only one shield. If more than one AC formula applies to you, you choose which to use.
Common armor values
These values are from the fifth edition player rules, and the 2014 and 2024 versions agree on the core numbers:
| Armor | Type | Base AC |
|---|---|---|
| Padded | Light | 11 + Dex |
| Leather | Light | 11 + Dex |
| Studded leather | Light | 12 + Dex |
| Hide | Medium | 12 + Dex (max 2) |
| Chain shirt | Medium | 13 + Dex (max 2) |
| Scale mail | Medium | 14 + Dex (max 2) |
| Breastplate | Medium | 14 + Dex (max 2) |
| Half plate | Medium | 15 + Dex (max 2) |
| Ring mail | Heavy | 14 |
| Chain mail | Heavy | 16 |
| Splint | Heavy | 17 |
| Plate | Heavy | 18 |
Check your own rulebook for prices, weight, and special notes, because they can differ between versions.
Armor proficiency, Strength, and Stealth
You can wear any armor, but if you are not trained in it, you take serious penalties: disadvantage on ability checks, saving throws, and attack rolls involving Strength or Dexterity, and you cannot cast spells. Your class tells you which armor you are trained in. Some heavy armors also list a Strength requirement, and if you do not meet it, your speed drops. Some armors impose disadvantage on Stealth checks, which matters if your character sneaks around.
Class features that change AC
- Barbarian Unarmored Defense: 10 + Dexterity modifier + Constitution modifier when wearing no armor. A shield is allowed.
- Monk Unarmored Defense: 10 + Dexterity modifier + Wisdom modifier when wearing no armor and no shield.
- Some other subclasses and species offer their own base AC formulas.
- Spells such as mage armor set your base AC to 13 + Dexterity modifier for a duration, and shield gives a temporary bonus as a reaction.
Magic items can add bonuses too, such as a +1 to armor or a shield.
Leather armor and the best medium armor
Leather armor has a base of 11, so it adds 1 on top of the 10 you would have anyway, plus your full Dexterity bonus. It is cheap and quiet. For medium armor, the highest base AC is half plate at 15, but it is costly and can impose disadvantage on Stealth. Breastplate has a base of 14 and does not impose that Stealth penalty, so players often like it. Which is best depends on your budget, Stealth needs, and Dexterity. If you have 14 or more Dexterity, medium armor gets you the full +2.
Worked example
Imagine a Fighter with a Dexterity of 14, which gives +2. Wearing chain mail (16) and carrying a shield (+2) gives an AC of 18. A Rogue with 16 Dexterity (+3) in studded leather (12) gets 15. Without a shield, a Monk with 16 Dexterity (+3) and 14 Wisdom (+2) has 10 + 3 + 2 = 15.
Is any class “the most overpowered”?
Players debate this, and the answer depends on the edition, the campaign, and the table. Armor class is only one part of what keeps a character alive; hit points, saving throws, and teamwork matter as well. For an overview of how classes compare, see our D&D class guide. New characters should also read the D&D character basics page for where AC fits in the build.