Armor Class (AC) is a fundamental concept in DnD combat that you need to understand in order to play. It’s important that you know what it is, what it does, and to some degree, how to calculate it.
Luckily, all of these three things aren’t particularly difficult to wrap one’s head around, but, nonetheless, the explanation of them is the goal of this article. So, how does Armor Class (AC) work in DnD 5e?
Armor Class is a value that determines how hard it is for characters to be hit. In general, a character that doesn’t wear armor has an AC of 10 plus their Dexterity modifier. If that character would be wearing armor, a fixed value would be added to that Dexterity modifier. If a character has an AC of 15, an attacker must roll 15 or higher on a d20 die to hit the character with its attack.
It’s completely fine if you don’t understand the concept right off the bat. Let’s go through the details of AC. After reading this article, you will hopefully have all the answers to your questions.
How Do Armor Class Work in 5e?
The concept of AC isn’t terribly deep. However, there is a lot of added complexity because of the different armor types and armor proficiencies.
Armor types are categorized into three different types: light, medium, and heavy armor. Generally, nimbler classes wear lighter armor while bulkier classes wear heavy armor.
Earlier, I mentioned that you use your Dexterity modifier to calculate your Armor Class. That is generally true, but not for Heavy armor.
Related Article: A Beginner’s Guide to Armor Class (AC) In Baldur’s Gate 3
For Light Armor, you simply add your Dexterity modifier to the sum of your base AC (10) and the armor piece. When reading information about armor in published DnD books, the base AC and armor are always calculated together. For example, Studded Leather is listed as having 12 AC. You don’t add your basic 10 AC to that.
Rather, the Studded Leather gives you +2 AC to your base AC, giving you a total of 12 (+Dex modifier). I’m just offering this information in case you’ve read what seems to be conflicting information.
There are a few exceptions to the rule of 10 unarmored AC, however. Monks and Barbarians both have the class trait Unarmored Defense, which gives them a bonus when not wearing any armor:
“While you are not wearing any armor, your armor class equals 10 + your Dexterity modifier + your Constitution/Wisdom modifier. You can use a shield and still gain this benefit.“
Monks use their Wisdom modifier for their unarmored defense, while Barbarians use their Constitution modifier.
So, here are the different armors for each type. As I mentioned earlier, you don’t add your Dexterity modifier to Heavy Armor. Heavy Armor has a Strength requirement that a character must meet in order to wear it.
In fact, Heavy Armor just adds a flat AC value. No modifiers are added to the calculation. Of course, the value that Heavy Armor adds is usually a lot higher than Medium and Light Armor.
With Medium Armor, you add your Dexterity modifier, but there’s a +2 limit. In other words, if you have a +3 Dexterity modifier and wearing Medium Armor, you get +2 AC from that, not 3.
Without further ado, here’s the table:
| Armor | Armor Class | Strength Requirement | Stealth Advantage/Disadvantage | Weight (lbs) |
| Padded Armor (Light) | 11 (+Dex mod) | – | Disadvantage | 8 lbs |
| Leather Armor (Light) | 11 (+Dex mod) | – | – | 10 lbs |
| Studded Leather Armor (Light) | 12 (+Dex mod) | – | – | 13 lbs |
| Hide Armor (Medium) | 12 (+Dex mod, max 2) | – | – | 12 lbs |
| Chain Shirt (Medium) | 13 (+Dex mod, max 2) | – | – | 20 lbs |
| Scale Mail (Medium) | 14 (+Dex mod, max 2) | – | Disadvantage | 45 lbs |
| Breastplate (Medium) | 14 (+Dex mod, max 2) | – | – | 20 lbs |
| Half Plate (Medium) | 15 (+Dex mod, max 2) | – | – | 40 lbs |
| Ring Mail (Heavy) | 14 | – | Disadvantage | 40 lbs |
| Chain Mail (Heavy) | 16 | 13 | Disadvantage | 55 lbs |
| Splint Armor (Heavy) | 17 | 15 | Disadvantage | 60 lbs |
| Plate Armor (Heavy) | 18 | 15 | Disadvantage | 65 lbs |
So, characters have AC, and armor has AC. However, there are more things that have AC in DnD. For example, shields. Shields adds a flat AC score to your character, making it more difficult to hit you.
Furthermore, objects/materials have AC. The harder the object is to break/deal damage to, the higher the AC. The easier it is to break/deal damage to, the lower the AC.
| Material | AC |
| Rope | 11 |
| Wood | 15 |
| Stone | 17 |
| Steel | 19 |
| Mithral | 21 |
| Adamantine | 23 |
| Tarrasque Carapace (+Resistances…) | 25 |
What Armor Should My Character Wear?
DnD places a big emphasis on internal logic, and that’s good because it’s a roleplaying game. All classes aren’t effective with every piece of armor, for example. A Wizard can’t just equip a massive plate armor and go to work.
What armor your character should wear depends entirely on its class. I’ll provide a list of the armor types that various classes are proficient with.
| Class | Armor Proficiency |
| Artificer | Light armor, medium armor, shields |
| Barbarian | Light armor, medium armor, shields |
| Bard | Light armor |
| Cleric | Light armor, medium armor, shields |
| Druid | Light armor, medium armor, shields (No metal armor) |
| Fighter | All armor, shields |
| Monk | – |
| Paladin | All armor, shields |
| Ranger | Light armor, medium armor, shields |
| Rogue | Light armor |
| Sorcerer | – |
| Warlock | Light armor |
| Wizard | – |
If all armors are available to you by virtue of a feat, racial trait, or multiclassing, then you can choose to wear whatever you want. The best option is oftentimes the one that grants you the most AC.
If you’re a character that sneaks around a lot, then avoid armor that gives you disadvantage on Stealth checks. Furthermore, if you have a +1 or 2 Dexterity modifier and Medium Armor is available to you, it’s probably a good idea to wear it since you aren’t punished by the Armor types modifier restriction, and you can’t make use of a good Dex modifier for Light Armor.
Whether or not any given armor type is available to you depends on your Armor Proficiency. Table 1 illustrates the classes’ different Armor Proficiencies. Let’s discuss it further.
Armor Proficiency in DnD
If you want to wear a certain Armor Type, make sure that you’re proficient in wearing it. If you aren’t proficient with the armor that you’re wearing, the following restrictions are put on you:
- You have disadvantage on any ability check, saving throw, or attack roll that involves Strength or Dexterity
- You can’t cast spells
As you can imagine, these debuffs are devastating, practically rendering your character useless. If you want to wear armor that you aren’t proficient in, there are solutions.
First, you must become proficient with them. This is possible in multiple ways. The most common way is arguably to specialize in another class (“multiclassing”) to gain other armor proficiencies.
This is possible for both Medium and Light armor, but not Heavy armor. If you want to be proficient in Heavy armor, you can take the Heavily Armored feat on level-up instead of increasing your stats.
There are more ways, although they are unorthodox and sometimes unavailable. Tenser’s Transformations lets a character gain martial skill and heavy armor proficiency for a time, for example, and Wish may let you be proficient in Heavy armor (depending on your DM).
How to Calculate Armor Class
How you calculate your Armor Class depends on what factors you have to consider. For example, if you’re a Barbarian, you can add your Constitution modifier to your AC without armor because of your class trait Unarmored Defense. I’ll go over the factors you have to consider below.
No Armor
Characters have 10 in base Armor Class then add their Dexterity modifier. If you’re a Barbarian, add your Constitution as well (10 + Dexterity modifier + Constitution modifier), and if you’re a Monk, add your Wisdom modifier (10 + Dexterity modifier + Constitution modifier).
The results with be your armor class without armor. It’s generally not very relevant since there’s no reason to not wear armor if you aren’t a Barbarian or Monk. Something to note is that characters can have a negative Dexterity modifier, and if they do, that’s calculated into their AC.
If you have a shield equipped, just add the shield’s AC to your base AC. Unarmored Defense is still retained if you’re using a shield.
Light Armor
Light armor uses a character’s Dexterity modifiers, so first of all, take note of that. Then, you add 11 to your Dexterity modifier if you have Padded Armor or Leather Armor, and 12 if you have Studded Leather Armor.
For example, if I have a +3 in Dexterity modifier and wear studded leather, I will end up with the base AC 15 (3 + 12).
Medium Armor
First of all, take note of your Dexterity modifier. If it is higher or equal to 2, you add +2 to the calculation. If your modifier is 1 or lower, add your Dexterity modifier to the calculation.
After this, just add together your noted Dexterity modifier with the Armor you’re wearing. 12 for hide armor, 13 for chain shirt armor, 14 for scale mail/breastplate, and 15 for half-plate armor.
So, if I have +4 in Dexterity modifier, I don’t get to use that to its full potential. Instead, I use +2, which is the Dexterity modifier cap for medium armor, and add it together with equipped armor.
Heavy Armor
Heavy armor is the easiest to calculate because it just adds flat AC without considering any modifiers:
- Base AC is 14 with the ring mail armor equipped
- Base AC is 16 with the chain mail armor equipped
- Base AC is 17 with the splint armor equipped
- Base AC is 18 with the plate armor equipped