How to Calculate Armor Class in D&D 5e

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Armor Class (AC) is one of the most important defensive stats in Dungeons & Dragons 5e. At its core, it represents how hard your character is to hit in combat, combining armor, agility, shields, magic and special abilities into a single number.

Despite its importance, AC is one of the rules that new players (and even veterans) can often get wrong. The good news? Once you break it down, calculating Armor Class in D&D 5e is actually pretty straightforward. Below, we’ve put together a step-by-step guide on how to calculate AC using the new 2024 D&D 5e rules.

• Step 1: Determine Your Base Armor Class
• Step 2: Add a Shield (If You’re Using One)
• Step 3: Apply Magical Bonuses
• Step 4: Add Miscellaneous Modifiers

Step 1: Determine Your Base Armor Class

Your base AC comes from the type of armor you’re wearing (if any).

No Armor

If your character isn’t wearing armor:

• Start with an AC of 10
• Add your Dexterity modifier (this can be negative)
• Barbarian: Also add your Constitution modifier
• Monk: Also add your Wisdom modifier

This total is your base Armor Class.

Light Armor

Light armor relies heavily on Dexterity.

• Start with your Dexterity modifier
• Add:
  • 11 for Padded or Leather armor
  • 12 for Studded Leather armor

This is your base Armor Class while wearing light armor.

Medium Armor

Medium armor balances protection and mobility, but limits Dexterity benefits. Your base AC cannot gain more than +2 from Dexterity while wearing medium armor.

• If your Dexterity modifier is +2 or higher, start with +2 AC
• If your Dexterity modifier is +1 or lower, add that modifier to your AC (even if it’s negative)
• Then add:
  • 12 for Hide armor
  • 13 for Chain Shirt
  • 14 for Scale Mail or Breastplate
  • 15 for Half Plate

This is your base AC while wearing Medium Armor.

Heavy Armor

Heavy armor provides a flat Armor Class and does not use Dexterity modifiers at all.

• Ring Mail: AC 14
• Chain Mail: AC 16
• Splint Armor: AC 17
• Plate Armor: AC 18

This is your base AC in heavy Armor.

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Step 2: Add a Shield (If You’re Using One)

If your character is wielding a shield and has training with it:

• Add +2 AC

You can only benefit from one shield at a time, and you must be proficient to gain its AC bonus. In the D&D 2024 rules you must also spend an action to equip or remove a shield (which can also impact your AC).

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Step 3: Apply Magical Bonuses

After calculating your base AC and shield bonus, apply any magical adjustments:

• Magic armor: Add its bonus (e.g., +1 Plate Armor)
• Magic shield: Add its bonus (e.g., +1 Shield)
• Other magic items: Rings, cloaks, spells or class features that explicitly increase AC

All of these stack unless a rule says otherwise.

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Step 4: Add Miscellaneous Modifiers

Finally, apply any situational or feature-based adjustments, such as:

• Class abilities
• Feats
• Spells (like Shield or Mage Armor)
• Temporary effects or conditions (including cover)

If a feature says it changes how AC is calculated, follow its specific rules carefully (some replace your normal calculation instead of adding to it).

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Final Armor Class Formula (At a Glance)

Armor Class = Base Armor AC + Shield bonus + Magical bonuses + Miscellaneous modifiers

That final number is your character’s Armor Class (AC).

Common AC Mistakes to Avoid

• Adding Dexterity to heavy armor (you don’t)
• Exceeding the +2 Dex cap on medium armor
• Using a shield without proficiency (you don’t get the +2 bonus)
• Forgetting magical or class-based bonuses
• Forgetting situational AC bonuses (such as cover or spell effects)
• Combining multiple armor calculations (you only use one)

A Table of All Armor By AC

Armor	Armor Type	Armor Class (AC)
Padded Armor	Light	11 + Dex modifier
Leather Armor	Light	11 + Dex modifier
Studded Leather Armor	Light	12 + Dex modifier
Hide Armor	Medium	12 + Dex modifier (max +2)
Chain Shirt	Medium	13 + Dex modifier (max +2)
Scale Mail	Medium	14 + Dex modifier (max +2)
Breastplate	Medium	14 + Dex modifier (max +2)
Half Plate Armor	Medium	15 + Dex modifier (max +2)
Ring Mail	Heavy	14
Chain Mail	Heavy	16
Splint Armor	Heavy	17
Plate Armor	Heavy	18
Shield	Shield	+2

Why Armor Class Matters

In the D&D 5e rules, AC directly determines how often enemies hit you. A difference of even 1 or 2 points can dramatically change how survivable your character is at the table (especially at low and mid levels). Understanding how AC works can also help you make smarter equipment choices and avoid accidentally breaking the rules. Once you’ve calculated it a few times, Armor Class becomes second nature and your chances of surviving your next dungeon crawl become that much better.

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