Armor Class (AC) is a cornerstone mechanic within DnD 5e, representing a character’s ability to fend off physical attacks using armor and shields. In this article, we will delve into the intricacies of calculating AC, explore its special rules, and offers strategic tips for utilizing AC to your advantage.

How to Calculate Armor Class (AC)

The calculation of the Armor Class (AC) in DnD 5e involves several steps to ensure comprehensive protection for your character:

Step 1: Determine Base AC

Begin by establishing your character’s base AC, representing their armorless defense, which represent their ability to avoid incoming attacks: this value is equal to 10 + their Dexterity modifier.

Step 2: Add Armor Bonus

Next, include the armor bonus from equipped armor. Refer to this table to determine the specific armor bonus. Remember that for medium/heavy armor, there is a limit in the value of the Dexterity modifier you can add with your Armor Bonus.
For instance, the scale mail contributes a +14 armor bonus to which you can add your Dexterity Bonus for a maximum value of two. So if you have a DEX modifier equal to +4, when you put on your Scale Armor your Armor Class will be:

Step 3: Add Shield Bonus

Utilizing a shield adds a +2 shield bonus to your AC.

Step 4: Add Special Dexterity Modifier

Incorporate your character’s Dexterity modifier to represent their agility in dodging or deflecting attacks. Note that armor type constrains the Dexterity bonus, like plate armor allowing up to +2 of the modifier.

How to increase Armor Class (AC) in DnD 5e

Armor

As you can notice from the previous paragraph, the most common way to increase the Armor Class value in DnD 5e is by using an Armor. The ability to use armor is directly linked to three key elements:

A. The class of the character

The character’s class determines the Armor Proficiency: which expresses the fact that, while everyone can potentially wear a shield or an armor, only those skilled in using specific armor types understand how to utilize them effectively. If you wear any protection without proficiency, you will have a disadvantage on Strength or Dexterity-related ability checks, saving throws, and attack rolls and your spellcasting will be restricted.

B. The ability scores of the character (Strenght)

In the case of Heavy Armors, it is crucial also to consider the physical strength of the character wearing it, since this type of armor interferes with the ability of the character to move quickly, and freely and to use their stealth. In this case, you must check if the character reaches the strength requirements of the armor: if the ability score is under the required value (for example the Chain Male has a STR 13 requirement) the wearer will have his/her speed reduced by 10 feet (3 meters).

C. Feats that influence the Armor Class Value

Feats in DnD 5e are also linked to the Class that you choose: many feats influence the way a character can defend himself/herself, but the following ones directly affect the AC (Armor Class):

• Defensive Duelist : With this feat you can use your reaction to add your proficiency bonus to your AC. Monks, Rogues, and Bards are the classes we suggest for this feat. PREREQUISITE: 13 DEX

• Dragon Hide – Among the many other benefits, it will increase your Base AC to 13, and your defence becomes 13 + your Dexterity modifier
• Dual Wielder – this feat gives you the master of fighting with two weapons, that will provide a +1 to your Armor Class
• Medium Armor Master – Add +3, rather than the standard +2, to your AC if you have a Dexterity of 16 or higher and wear a Medium Armor
• Shield Master – You can add your shield’s AC bonus to any Dexterity saving throw. This means that you can interpose your shield between you and the source of the attack and, so, you can use this bonus for every Dexterity check against a spell or other harmful effect that targets you. This feat also comes handy since if you succeed in a saving throw to take only half the damage, you take no damage instead.

Stealth:  when the Armor table shows “Disadvantage” in the Stealth column, it means that the wearer has disadvantage on Dexterity (Stealth) checks.

Magic Items

Magic Items, even in a setting full of magic like DnD, are both expensive and rare. However if your PC is lucky enough to find one of the following items, he will be able to increase his/her armor class substantially:

Within this array of equipment, some items augment the protective capabilities of adventurers. These items bolster an individual’s Armor Class (AC), contributing to their overall resilience in the face of danger. Each item mentioned below augments this critical attribute, safeguarding adventurers from harm in various ways:

• Armor +X: This refers to armor upgrades that offer a direct increase in AC. The numerals (X) indicate the amount of the enhancement, whether it’s +1, +2, or +3 AC.
• Arrow-Catching Shield: This specialized shield enhances AC by +2 against ranged attacks. It also boasts additional effects tailored to thwart projectile assaults.
• Cloak of Protection: This enchanted cloak elevates AC by +1 and grants an elevated chance to resist harmful effects by bestowing the same bonus to all saving throws.
• Demon Armor: Aside from its inherent qualities, this ominous armor bestows a +1 AC augmentation to its wearer.
• Dragon Scale Mail: Draped in dragon scales, this unique armor provides a +1 AC enhancement as part of its formidable attributes.
• Dwarven Plate: Known for its resilience, Dwarven Plate armor boosts AC by +2, further securing its wearer against attacks.
• Elven Chain: This finely crafted armor complements AC with a +1 bonus, a testament to its intricate design and protective properties.
• Glamoured Studded Leather: This elegantly concealed armor enhances AC by +1 and exhibits enchantments for various purposes.
• Ioun Stone (Protection): A floating gemstone companion, this magical item contributes to AC with a +1 bonus, a mere hint of its potential capabilities.
• Ring of Protection: Adorning this ring not only enhances AC by +1 but also fortifies an individual’s resistance to adverse effects, sharing its bonus with all saving throws.
• Shield +1/2/3: Shields inherently grants a +2 AC boost, so the numeric value corresponds to the incremental enhancement. A +1 shield elevates AC by +3, while a +2 offers +4, and a +3 imparts +5 AC.
• Staff of Power: This impressive magical staff bolsters AC by +2 and reinforces the user’s resilience against detrimental effects, accompanied by a host of additional benefits.

Racial Traits

Few races grant an inherent bonus to Armor Class (AC), as such a bonus at the outset can significantly impact a character’s defense. Among the races introduced in supplemental sources that provide an AC boost are:

• Tortle: Through their Natural Armor trait, Tortles see their base AC elevated to 17. Additionally, they can employ Shell Defense, an ability that bolsters AC by an impressive +4 and other advantages.
• Warforged: These remarkable beings, characterized by integrating organic and constructed components, possess the Integrated Protection trait. This ability contributes to a +1 enhancement to their AC, reflecting the synergy between their unique form and protective mechanisms.

Special Rules and Tips

Not every character/enemy wears armor, so how do you calculate the Armor Class (AC) in DnD 5e for these instances? There are three different versions in which it is possible to calculate the defence of the Characters:

• Natural Armor
• Unarmored defense
• Defensive spells

Natural Armor (Creatures & Monsters)

Certain creatures possess natural armor (e.g., dragons) that supplements or substitutes their AC alongside equipped armor.

In Dungeons and Dragons 5th Edition, natural armor refers to a type of protective barrier that certain creatures possess innately, without the need for traditional armor or equipment. Natural armor represents the physical toughness, thick hide, scales, or other innate physical defenses that grant these creatures an enhanced resistance to attacks and damage. Instead of wearing manufactured armor, creatures with natural armor rely on their own physical attributes to shield themselves from harm.

The concept of natural armor is a way to represent the inherent durability of creatures that have evolved or developed specialized defenses through their biology, magical nature, or other supernatural attributes. These defenses can include thick skin, scales, bony plates, tough hide, magical barriers, or other traits that provide additional protection.

Natural armor is factored into the equation when determining a creature’s Armor Class (AC) in DnD 5e. A creature’s natural armor bonus is usually a fixed number added to its base AC, reflecting the increased difficulty of successfully hitting the beast due to its natural defenses: the specifics of a creature’s natural armor bonus can vary depending on the creature’s type, size, and abilities.

It’s important to note that natural armor does not usually stack with manufactured armor or magical armor. If a creature has both natural armor and wears armor, the game mechanics typically dictate that the creature only benefits from the highest AC bonus between the two sources. For example, if a creature has a natural armor bonus of +3 and wears armor that grants a +2 bonus, they would use the +3 natural armor bonus for their AC calculation.

Creatures with natural armor include various fantastical beings such as dragons, certain types of beasts, aberrations, and magical creatures like elementals. The presence of natural armor adds diversity to creature types within the D&D world, allowing for unique challenges and encounters for players.

In summary, natural armor in D&D 5e represents the innate physical defenses possessed by particular creatures.

Unarmored Defence

This capability is accessible mainly to the monk and barbarian classes, offering an alternative method of determining your Armor Class (AC) when eschewing the use of conventional armor.

• Barbarian: For the Barbarian’s Unarmored Defense, the calculation is derived from 10+ Dex Modifier + Constitution Modifier
• Monk: Conversely, the Monk’s Unarmored Defense is 10 + Dexterity modifier + the Wisdom modifier.
  These calculations introduce an additional modifier to the standard computation for characters relying on unarmored protection. Such specific calculations are tailored to the distinctive attributes paramount for each class.
• Sorcerer (variation): In a similar vein, the Draconic Bloodline Sorcerer presents a variant of this attribute known as Draconic Resilience. In conjunction with other inherent abilities, this sorcerous origin empowers the character to establish their unarmored AC utilizing the formula 13 + Dex Modifier.

Additional Spells and Abilities

In the same way as Magic Items, also some specific spells (e.g., mage armor) can help you in protecting your character.

Here are three examples of spells in Dungeons and Dragons 5th Edition that increase a character’s Armor Class (AC):

• Magic armor: It provides a +3 AC bonus. . This spell is handy for characters who use magic (like Sorcerers or Warlock) since they are not proficient even with light armor and must rely only on their dexterity.
• Shield of Faith: This spell grants a target a +2 bonus to their AC for the spell’s duration, which is up to 10 minutes. It’s a useful spell for providing a short-term boost to a character’s defenses in combat situations.
• Haste: While Haste is primarily known for its effect on speed and granting an extra action, it also grants a +2 bonus to AC. This makes the target harder to hit and provides additional protection.
• Barkskin: this spell sets the target’s AC to a minimum of 16, regardless of their Dexterity modifier or any other modifiers. This is particularly useful for characters with low Dexterity scores, ensuring they have a decent AC.

Tips for the defense of your character

When you are creating your Character and want to provide the best defense possible, you should keep in mind the following five elements:

1. Armor Selection: Choose appropriate armor types for your character’s strengths and limitations. Heavy armor might offer higher AC but restrict mobility, while lighter armor prioritizes agility.

2. Dexterity Emphasis: Even with Heavy Armor, Dexterity bolsters your armor class. Invest in your dexterity and consider choosing races and classes with special Dexterity Abilities for more excellent defense.

3. Shield Synergy: Combine armor with a shield to augment your AC by an additional +2. This synergistic approach significantly boosts your defenses.

4. Magic Augmentation: Explore magic items, like bracers of defense or a ring of protection, to bolster AC beyond standard equipment limits. Tailor your choices to your character’s overall build.

5. Cover Utilization: Strategically position your character for cover during combat. Objects and terrain can provide half or three-quarters cover, granting AC bonuses. Make the most of cover to minimize potential damage.

Final Notes: Armor Class (AC) in DnD 5e

Understanding Armor Class (AC) in Dungeons and Dragons 5e empowers you to optimize your character’s defense strategy. By comprehending the calculation process, grasping special rules, and implementing strategic tips, you can wield AC effectively to shield your character from harm and emerge victorious in your tabletop adventures.

Credits

The Armor Class (AC) is one of most important elements in DnD 5e, here are the sources we used to create this guide on how to use it:

1. Learn more about the Armor Class
2. Here is another article regarding the AC in D&D
3. Discover on how does Cone Spells in the word’s most played TTRPG with our article
4. Learn more about Movement in DnD with our article