What Is the Base AC When Not Wearing Armor (DnD 5e)?

Many character classes such as Sorcerer, Monks, Wizards, and Barbarian do not commonly wear any armor in D&D. Monks, Barbarians, and ancestry sorcerers have unarmored defense perks to boost their AC. However, Wizards do not have such a perk, which baffles many D&D players about what is the AC (Armor Class) of those character classes who do not wear armor?

This article will guide you about the formula to calculate the base of unarmored characters and explain the base AC: what it is and how to calculate it for different types of Armor in D&D 5e

How do you calculate unarmored AC in D&D 5e?

According to the rules mentioned in chapter 1, page 14 of the PHB (Player’s handbook), the AC of a character without any armor or shield is 10+ the character’s Dexterity Modifier. A dexterity modifier is +2, so the AC of the unarmored character would be = 10 +2 = 12. It is the default and most simple formula to calculate the AC of an unarmored character. 

The game rules do not consider the shield and the armor as the same thing. So, the AC with a shield but no armor is= 10 + Dexterity modifier + shield (+2) because shields are a bonus, so when you wear a shield, you get +2 AC. The AC of an unarmored character with a shield is = 10 + 2 (Dexterity modifier) + 2 (shield bonus), total = 10 + 2 + 2 = 14 AC.

The AC of a Barbarian not wearing armor is = 10 + Dexterity (DEX) modifier + CON (Constitution) modifier. 10 + 2 (DEX) modifier + 2 (CON) modifier.

Unarmored AC of character at level 1  based on his or her Ability, Ability Score, and Ability Modifier.

AbilityAbility ScoreAbility Modifier

Now that we know the formula to calculate an unarmored character’s base AC (Armor Class) let us explore the base AC in detail.

What Exactly Is “Base AC” in D&D 5E?

The “base AC” is the AC you calculate without adding any modifiers. However, it is not defined in the game because it has little or no use outside the Mage Armor spell. These modifiers may include:

  • Class-based bonuses like from any Fighting Style
  • Magic bonuses from Magic items
  • Temporary ability bonuses from spells
  • Any other thing not included in this list

So your “base AC” might be your armor + your ability (+10, if accessible or applicable) plus the Dexterity modifier (+2) plus your shield (+2). So base AC = 10 + Dexterity Modifier (+2) + shield bonus (+2) = 10 + 2 + 2 = 14.

Or it could be your natural armor plus your Dex or other stats applicable. Also, the Mage Armor would increase your “base” AC from 10 to 13 + Dex.

Your base AC could include any applicable stat bonuses. In the case of Mage aroma, the base AC is 13 + Dex without adding any additional bonus. The shield increases your base AC by +2. 

The base AC for the following types of armor is:

No Armor

ArmorCostAC (Armor Class)StrengthStealthWeight
None10 + Dex modifier

Light Armor

ArmorCostAC (Armor Class)StrengthStealthWeight
Padded5 gp11 + Dex modifierDisadvantage8 lb.
Leather10 gp11 + Dex modifier10 lb.
Studded leather45 gp12 + Dex modifier13 lb.

Medium Armor

ArmorCostAC (Armor Class)StrengthStealthWeight
Hidden10 gp12 + Dex modifier (max 2)12 lb.
Chain Shirt50 gp13 + Dex modifier (max 2)20 lb.
Breastplate45 gp14 + Dex modifier (max 2)20 lb.
Half plate750 gp15 + Dex modifier (max 2)Disadvantage40 lb.

Heavy Armor

ArmorCostAC (Armor Class)StrengthStealthWeight
Ring mail30 gp14Disadvantage40 lb.
Chain mail75 gp16Str 13Disadvantage55 lb.
Splint200 gp17Str 15Disadvantage60 lb.
Plate1500 gp18Str 15Disadvantage65 lb.


Shield10 gp+26 lb.

Various other factors establish your base AC but it depends on your AC and the appropriate stat. 


What Is the Lowest Possible AC?

The lowest possible AC (Armor Class) in D&D is -7. If you want to achieve this ludicrous AC of -7, these are the conditions you need to fulfill: 

The Character

Suppose a character wants to accomplish the lowest possible AC. In that case, his rolled ability scores should result in 3 Dexterity, 3 Charisma, and 3 Wisdom (should be level 1 Monk), or 3 Constitution (should be level 2 Barbarian).

The Gear

The character also needs these magic items:

  • Chromatic Dragon Mask (available in Hoard of the Dragon Queen and Rise of Tiamat module)
  • Book of Vile Darkness
  • Wand of Orcus, Sword of Kas, or Orb of Dragonkind

The Calculation

Now let us see how the AC could result in -7:

  1. With Dexterity and Constitution or Wisdom at level 1, the AC with Unarmored Defence is 0. However, if you do not wear any armor, your AC is 10 + your Dexterity modifier + your Constitution modifier (or Wisdom modifier for a monk. 
  1. The AC of a Chromatic Dragon Mask could have the following effect: If the Dragonic Majesty wears no armor, you can add a Charisma bonus to your Armor Class. The resultant AC would be -5. 
  2. The slow spell: The speed of an affected target will be half, and it would take the penalty of -2 to AC and Dexterity saving throws. It cannot use reactions.

The calculation for the lowest AC = -2 (slow spell) + (-5 from Chromatic Dragon Mask):

 -2 + -5 = -7 AC (Armor Class)

However, another calculation suggests that the lowest possible AC could be -5 by fulfilling the following requirements:

Requirements your character must fulfill:

  • A Monk class of at least level 1
  • Your ability scores must include 3 Dexterity and 3 Wisdom.
  • You should not wear any armor.
  • You should have access to someone who can cast the slow and feeblemind spells.
  • You must have a Dragon Mask and be playing the Rise of Tiamat adventure module.

Calculation of AC

Here is the easy method to calculate your AC:

  • Unarmored Defense of the monk sets your AC to 10 + Dexterity bonus (-4) + Wisdom bonus (-4), the total = 10 – 4 – 4 = 2.
  • The feeblemind spell drops your Charisma score to 1, and if you wear the Dragon Mask, add a Charisma bonus (-5) to AC.
  • If you are affected by a slow spell, the penalty is -2 to AC.

Total AC = 10 – 4 (Dex) – 4 (Wisdom) – 5 (Charisma bonus) – 2 (slow spell) = 10 – 4 – 4 – 5 – 2 = – 5 of Total AC

Do You Get a Proficiency Bonus to AC?

No, you do not get a Proficiency bonus to AC because Proficiency only allows you to don that wear that armor which does suffer disadvantage on all rolls (involving Strength or Dexterity). It is mechanically identical to the armor of 3.5 proficiency that can remove a penalty associated with donning an armor you are not proficient with. Apart from that, it serves no other purpose and maybe just a requirement for certain feats.


Is Strength Modifier Also Added While Adding Proficiency Bonus in Attack Roll?

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