D&D 5e AC Calculator: How to Calculate Armor Class

D&D 5e Armor Class (AC) Progression Chart

This chart illustrates how different armor types and unarmored defenses scale with your Dexterity modifier, assuming no other bonuses. Note the Dexterity cap for Medium Armor.

Common D&D 5e Armor Types and Their Base AC

What is Armor Class (AC) in D&D 5e?

Armor Class, or AC, is a fundamental combat statistic in Dungeons & Dragons 5th Edition that represents how difficult it is to hit your character or a creature. When an attacker makes an attack roll, they roll a 20-sided die (d20) and add their attack modifier. If the total equals or exceeds the target's AC, the attack hits. A higher AC means your character is harder to hit, making them more resilient in combat.

Understanding how to calculate AC in D&D is crucial for character creation and combat planning. It's not just about wearing the heaviest armor; it's about combining various factors like Dexterity, shields, magical enhancements, and class features to achieve the optimal defense for your character's build.

Who Should Use This D&D 5e AC Calculator?

• New Players: Get a clear understanding of how AC is determined for your first character.
• Experienced Players: Quickly verify AC for new builds, multiclass characters, or when acquiring new gear.
• Dungeon Masters (DMs): Easily calculate AC for custom monsters or NPCs.
• Theorycrafters: Experiment with different armor types and ability scores to optimize defense.

Common Misunderstandings About D&D AC Calculation

Many players, especially beginners, often make mistakes when calculating AC. The most common issues include:

• Dexterity Modifier Caps: Forgetting that Medium Armor caps your Dexterity modifier bonus at +2, and Heavy Armor ignores your Dexterity modifier entirely.
• Unarmored Defense: Confusing the specific ability score modifiers (Wisdom for Monks, Constitution for Barbarians) or thinking they stack with actual armor. They don't.
• Stacking Bonuses: Misunderstanding which AC bonuses stack. Generally, different sources of AC (e.g., armor, shields, magic items) add up, but features that provide an alternative AC calculation (like Unarmored Defense) usually replace the base AC calculation, not add to it.
• Magical Armor vs. Spells: Distinguishing between a permanent bonus from magical armor (+1 Plate) and a temporary spell effect (Shield of Faith). Both add to AC, but their source and duration differ.

How to Calculate AC in D&D 5e: The Formula and Explanation

The core formula for Armor Class in D&D 5th Edition is highly dependent on whether your character is wearing armor, what type of armor it is, or if they have a special unarmored defense feature. All values are unitless integers.

General Rule: You usually only benefit from one AC calculation method at a time. For example, if you have Unarmored Defense and wear armor, you must choose which method to use, you don't add them together.

Core AC Calculation Methods:

The base AC is the foundation, to which other modifiers are added:

• Unarmored (No Special Feature): 10 + Dexterity Modifier
• Light Armor: Armor's Base AC + Dexterity Modifier
• Medium Armor: Armor's Base AC + Dexterity Modifier (max of +2)
• Heavy Armor: Armor's Base AC (Dexterity modifier is ignored)
• Monk Unarmored Defense: 10 + Dexterity Modifier + Wisdom Modifier
• Barbarian Unarmored Defense: 10 + Dexterity Modifier + Constitution Modifier
• Draconic Resilience (Sorcerer Feature): 13 + Dexterity Modifier

Once you have your base AC from one of these methods, you add other applicable bonuses:

Final AC = Base AC (from method above) + Shield Bonus + Magic Item/Spell/Other Bonuses

Variable Explanations:

Practical Examples of D&D 5e AC Calculation

Let's look at a few common character builds to illustrate how to calculate AC in D&D 5e using the rules above.

Example 1: A Fighter in Plate Armor with a Shield

• Inputs:
  • Base AC Source: Heavy Armor (Plate Armor)
  • Base AC Value: 18 (from Plate Armor)
  • Dexterity Modifier: +0 (Heavy Armor ignores Dex)
  • Constitution Modifier: N/A
  • Wisdom Modifier: N/A
  • Using a Shield: Yes (+2)
  • Magic Item/Spell/Other Bonus: +0
• Calculation:
  • Base AC (Plate Armor): 18
  • Dexterity Contribution: 0 (ignored)
  • Shield Bonus: +2
  • Magic/Other Bonus: +0
  • Final AC: 18 + 0 + 2 + 0 = 20
• Result: This Fighter has an impressive AC of 20, making them very hard to hit.

Example 2: A Monk with High Dexterity and Wisdom

• Inputs:
  • Base AC Source: Monk Unarmored Defense
  • Base AC Value: 10 (base for Unarmored Defense)
  • Dexterity Modifier: +4 (Dex 18-19)
  • Constitution Modifier: N/A
  • Wisdom Modifier: +3 (Wis 16-17)
  • Using a Shield: No (Monks typically don't use shields)
  • Magic Item/Spell/Other Bonus: +1 (e.g., from a Cloak of Protection)
• Calculation:
  • Base AC (Monk Unarmored Defense): 10
  • Dexterity Contribution: +4
  • Wisdom Contribution: +3
  • Shield Bonus: +0
  • Magic/Other Bonus: +1
  • Final AC: 10 + 4 + 3 + 1 = 18
• Result: This Monk has an AC of 18, relying on their agility and mental discipline rather than heavy armor.

Example 3: A Rogue in Studded Leather

• Inputs:
  • Base AC Source: Light Armor (Studded Leather)
  • Base AC Value: 12 (from Studded Leather)
  • Dexterity Modifier: +3 (Dex 16-17)
  • Constitution Modifier: N/A
  • Wisdom Modifier: N/A
  • Using a Shield: No
  • Magic Item/Spell/Other Bonus: +0
• Calculation:
  • Base AC (Studded Leather): 12
  • Dexterity Contribution: +3
  • Shield Bonus: +0
  • Magic/Other Bonus: +0
  • Final AC: 12 + 3 + 0 + 0 = 15
• Result: This Rogue has an AC of 15, which is typical for a lightly armored, agile character.

How to Use This D&D 5e AC Calculator

Our D&D 5e AC Calculator is designed to be intuitive and accurate, helping you quickly determine your character's Armor Class. Follow these simple steps:

1. Choose Your Base AC Source: Select the option that best describes your character's primary defense. This could be "Unarmored," a specific armor type (Light, Medium, Heavy), or a class feature like "Monk Unarmored Defense" or "Barbarian Unarmored Defense."
2. Adjust Base AC Value (If Applicable): If you chose a specific armor category (Light, Medium, Heavy) or "Custom Base AC," you can input the exact base AC provided by that armor (e.g., 12 for Studded Leather, 14 for Scale Mail). The calculator will pre-fill common defaults for armor types.
3. Enter Your Ability Modifiers: Input your character's current Dexterity modifier. If you selected "Monk Unarmored Defense," also input your Wisdom modifier. If you selected "Barbarian Unarmored Defense," input your Constitution modifier. Remember, modifiers are derived from your ability scores (e.g., a score of 10-11 is +0, 12-13 is +1, 14-15 is +2, etc.).
4. Check "Using a Shield?": If your character is actively wielding a shield, check this box to apply the +2 AC bonus.
5. Add Magic/Other Bonuses: Enter any flat bonuses to AC from magical items (like a +1 shield or +1 plate armor), spells (like *Shield of Faith*), or other specific class/feat features.
6. View Your Result: The "Your Calculated Armor Class" section will update in real-time, showing your final AC prominently, along with intermediate values for your base AC, Dexterity contribution, and other modifiers.
7. Use the "Reset" Button: If you want to start over or try a new build, click the "Reset" button to restore all inputs to their default values.
8. Copy Results: Use the "Copy Results" button to quickly grab your full AC breakdown for your character sheet or notes.

This calculator handles all the nuances of D&D 5e AC calculation, including Dexterity caps for medium armor and the specific ability score interactions for unarmored defense features, ensuring an accurate result every time.

Key Factors That Affect How to Calculate AC in D&D

Many elements contribute to a character's Armor Class in D&D 5e. Understanding these factors is essential for building an effective and resilient character.

1. Armor Type and Category

   This is arguably the most significant factor. Light, Medium, and Heavy armor categories determine the base AC and how your Dexterity modifier is applied (or not applied). For instance, a character in heavy armor will have a high base AC but gains no benefit from a high Dexterity score, while a lightly armored character relies heavily on Dexterity.

2. Dexterity Modifier

   Your Dexterity ability score modifier is crucial for most AC calculations. It directly adds to AC for unarmored characters, light armor wearers, Monks, Barbarians, and Draconic Sorcerers. For medium armor, it's capped at +2, regardless of how high your Dexterity modifier is. Heavy armor users ignore Dexterity entirely for AC.

3. Shields

   Wielding a shield consistently grants a +2 bonus to AC. This is a straightforward and effective way to boost defense, available to many classes proficient in shields. Remember that two-handed weapons or certain spellcasting components might prevent shield use.

4. Class Features and Racial Traits

   Many classes and some races offer unique ways to calculate or improve AC. Examples include:

   • Monk's Unarmored Defense: Adds Wisdom modifier to AC.
   • Barbarian's Unarmored Defense: Adds Constitution modifier to AC.
   • Draconic Resilience (Sorcerer): Provides a base AC of 13 + Dexterity modifier.
   • Warlock's *Armor of Agathys* or Paladin's *Shield of Faith*: Spells that can temporarily increase AC.

5. Magic Items and Spells

   Magical armor (e.g., +1 Plate Armor) provides a flat bonus to AC. Other magic items like Cloaks of Protection or Rings of Protection can also add to AC. Spells like *Shield* (reaction for +5 AC for one round) or *Protection from Evil and Good* can provide situational defensive boosts. These bonuses typically stack unless they are from the same source or explicitly state otherwise.

6. Feats

   Certain feats can also influence your AC. For example, the Defensive Duelist feat allows you to use your proficiency bonus to increase your AC against a single melee attack when wielding a finesse weapon. The Medium Armor Master feat removes disadvantage on Stealth checks for medium armor and increases the max Dex bonus for medium armor to +3, improving its scaling.

Frequently Asked Questions About D&D 5e Armor Class

Q1: Can I stack multiple unarmored defense features (e.g., Monk and Barbarian)?

A: No. If you have multiple features that give you different ways to calculate your AC (like Monk's Unarmored Defense and Barbarian's Unarmored Defense), you must choose which one to use. They do not stack.

Q2: Does my Dexterity modifier still count if I wear heavy armor?

A: No. Heavy armor explicitly states that you do not add your Dexterity modifier to your Armor Class. Your AC is simply the base AC of the armor.

Q3: What's the maximum Dexterity modifier I can add to Medium Armor AC?

A: For Medium Armor, your Dexterity modifier bonus to AC is capped at +2. So, if your Dexterity modifier is +3 or higher, you still only add +2 to your AC from Dexterity.

Q4: Do magic weapon bonuses add to AC?

A: No. A magic weapon (e.g., a +1 Longsword) adds to your attack rolls and damage rolls, but it does not directly add to your Armor Class. Only magic items specifically designed to enhance defense (like magical armor, shields, or protective rings/cloaks) affect AC.

Q5: Can I add a shield bonus to my Unarmored Defense AC?

A: Yes, generally. If your character is proficient with shields and is wielding one, you can add the +2 shield bonus to your AC, even if your base AC comes from an unarmored defense feature like a Monk's or Barbarian's. However, some class features might restrict shield use (e.g., Monks typically don't use shields to gain their full benefits).

Q6: What is the highest possible AC in D&D 5e?

A: While theoretical maximums can be very high with specific builds, magic items, and temporary spell effects, a realistic high AC for a well-built character is usually around 20-22 (e.g., Plate Armor + Shield + magic bonuses). With temporary spells like *Shield* or *Haste*, it can temporarily reach 25-27 for a round.

Q7: Why is it important to know how to calculate AC in D&D?

A: Knowing how to calculate AC ensures your character sheet is accurate, which is vital for fair gameplay. It also helps you make informed decisions during character creation and leveling up, allowing you to optimize your character's survivability and understand how different gear and abilities impact your defense.

Q8: If I wear armor, do I still get my Unarmored Defense bonus?

A: No. Unarmored Defense features (like those of Monks and Barbarians) specify that they apply "while you are not wearing armor." If you wear armor, you use the armor's AC calculation method instead.

Related D&D Tools and Resources

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• D&D 5e Character Builder: Create and manage your characters with ease.
• D&D Ability Score Calculator: Determine your ability modifiers from your scores.
• D&D Spell Slot Calculator: Manage your spell slots for casting classes.
• D&D Damage Calculator: Figure out your average damage output.
• D&D Proficiency Bonus Guide: Understand how your proficiency bonus works.
• D&D Saving Throw Calculator: Calculate your saving throw bonuses.
• D&D Hit Points Calculator: Track your character's health.
• D&D Feat Guide: Explore various feats to customize your character.