How Armor Class Really Works in DnD 5e [And How to Improve It]

How Does Armor Class Work in D&D 5e

Armor Class is a number representing the difficulty to hit a character or monster. For Players it is typically between 10 and 20. AC is determined by the armor worn, plus any modifiers. Your Armor Class is compared to any Attack roll against you. If your Armor Class is higher than the hit roll, the attack is unsuccessful.

For example, a Rogue with an armor class of 15 is attacked by a Goblin. The goblin attacks and rolls a 12. It gets a +2 bonus to hit due to his Dexterity bonus, for a total of 14. Since 14 is below the Rogues Armor Class, this is a miss.

As a DM, I like to explain what happened as a visual… so I might say “The Goblin slashes at you, but you deftly step aside and avoid the blow!” This is more in line with a nimble character like the Rogue. For a Fighter, the attack might glance off his armor or shield.

So let’s go into how we calculate Armor Class and more.

How to Calculate Armor Class in DnD 5e

Base Armor Class for unarmored player characters is 10. Add your Dexterity Modifier to the base 10 for your total. If you wear Armor, replace the 10 with the Base AC of that Armor Type. For Light and Medium Armor, you can still add your Dexterity modifier to this number. For Heavy Armor, Dexterity bonuses do not apply.

Example: Balin the Fighter has a Dexterity of 12. His base armor class without any gear is 10, plus his Dex modifier of +1, for a total of Armor Class 11.


Balin considers picking up Hide Armor. Armor Class 12 + his Dex modifier (+1 in this case). That would get him up to 13 AC!

But wait, for 20 more gold he could get Ring Mail. Ring Mail is Heavy Armor so he doesn’t get the +1 from Dexterity, but the base is Armor Class14.

On top of that, he decides to get a shield, which increases his armor class by 2. Giving him a grand total of Armor Class 16.

Armor Classes Diagram DnD 5e

Creatures and characters we come up against will have set ACs, decided by the DM or by a preexisting stat block. When it comes to figuring out our own armor class, however, there can be quite a few things that go into it. Don’t worry, we’ll make this nice and simple. 

Your armor class is, unsurprisingly, decided by what armor you are wearing, although there are a few exceptions we’ll get into later. 

In the table below, the different types of armor you can wear are split into the categories of light, medium, and heavy armor.

Anyone can wear any of these types of armor, but putting these on without proficiency in the armor type will cause you to have disadvantage on any attack rolls, ability checks, or saving throws that require strength or dexterity.

Not having proficiency in the armor you’re wearing also means losing the ability to cast spells.

Light Armor

ArmorCostArmor Class (AC)StrengthStealthWeight
Padded5 gp11 + Dex modifierDisadvantage8lbs
Leather10 gp11 + Dex modifier10lbs
Studded Leather45 gp12 + Dex modifier13lbs

Medium Armor

ArmorCostArmor Class (AC)StrengthStealthWeight
Hide10 gp12 + Dex modifier (max 2)12lbs
Chain Shirt50 gp13 + Dex modifier (max 2)20lbs
Scale Mail50 gp14 + Dex modifier (max 2)Disadvantage45lbs
Breastplate400 gp14 + Dex modifier (max 2)20lbs
Half Plate750 gp15 + Dex modifier (max 2)Disadvantage40lbs

Heavy Armor

ArmorCostArmor Class (AC)StrengthStealthWeight
Ring Mail30 gp14Disadvantage40lbs
Chain Mail75 gp16Str 13Disadvantage55lbs
Splint200 gp17Str 15Disadvantage60lbs
Plate1,500 gp18Str 15Disadvantage65lbs

There are a few things you’ve probably noticed, so let’s talk about the different qualities armor can have.

The column labeled strength is not necessarily a requirement. Rather, these armors can slow down a wearer’s movement by 10 ft unless they meet the strength minimum listed.

So a cleric wearing extremely heavy plate armor is going to need a lot of strength just to move around in it.

You’ll also see the stealth column. This is pretty straightforward. Some armor is noisy, as you move around it clinks and clanks and draws attention. This is inconsequential most of the time, but leads to disadvantage on stealth checks.

So the most important part of armor, the reason we’re here, is that it sets your base AC. Each armor lists exactly what your normal AC while wearing that armor will be.

For heavy armor, this is extremely straightforward, your AC is the number listed. Most other armors add your dexterity modifier to the AC, meaning you’ll want to make sure you don’t have a dexterity score of any lower than 10.

Having to take a loss to your AC because of a poor dexterity modifier would just be awful. 

It’s also important to note that medium armors have a maximum dexterity bonus of +2. Even if you have a +5 dex bonus, you’re only receiving so much of that while wearing medium armor. If this applies to your character, it might be a better idea to pick up some light armor.

Base AC

Throughout the many published works of 5e D&D, and this article, you’ll see the term “base AC”. Armor and other abilities set your base AC, meaning that any other abilities which increase your AC will be added on top of that number.

If you have multiple abilities vying for your base AC at any given time, you take the higher of the two, the abilities do not stack.

YOU DO NOT ADD YOUR PROFICIENCY BONUS TO AC.

This comes up frequently, so I want to make sure you fully understand that proficiency in an armor type only matters when it comes to the effects of wearing the armor. There is no extra bonus you receive for being proficient in a type of armor.

Difficulty to Hit Calculations

We use the table below to roughly gauge the difficulty, anywhere from very easy to nearly impossible. 

Difficulty to HitAC
Very Easy5
Easy10
Medium15
Hard20
Very Hard25
Nearly Impossible30

In order to actually hit anything in D&D 5e we use a d20, a twenty-sided dice. If I need to hit a goblin, which has an AC of 15, I’ll have to roll a 15 or higher. This means there’s a 25% chance that the average person hits a goblin; medium difficulty.

Fortunately for you, most player characters in D&D aren’t average people. We have impressive abilities that often give us bonuses whenever we try to attack our foes.

Even a low-level barbarian might have something like a +6 bonus to weapon attacks. If she were to swing her sword at a goblin she’d only have to roll a 9 or higher, making it much easier.

Unfortunately for you, most creatures you come up against will have their own abilities and bonuses that make it easier for them to hit you.

Having a good AC matters for both you and your opponents. While AC isn’t the only thing that matters in combat, it is incredibly important in deciding the victors.

Alternate AC Calculations

Not every character wears armor, so how do we calculate the AC of the armorless? There are a few different versions of this we might run into.

  • No armor
  • Natural Armor
  • Unarmored Defense
  • Spells 

No armor. A character with no armor and no other abilities has a base AC equal to 10 + their dexterity modifier. A character that has no armor proficiencies and no additional abilities acting on them will likely use this until they are under the effects of something that could give them a higher base AC or otherwise increase their AC

Natural armor. Certain races have natural armor, in which their AC is set by a racial ability. This is extremely common among creatures you might come across, but there are a few playable races that have a natural armor calculation for AC. 

The tortle is an excellent example of this, with a natural armor that sets your AC at 17. The ability for the tortle also states that you gain no benefits from wearing armor, but that you can wield a shield to increase your AC as normal. We’ll talk more about ways to increase your AC below.

Unarmored Defense. This feature is available to the monk and barbarian classes and gives an alternate way of calculating your AC when not wearing armor. 

  • Barbarian Unarmored Defense: 10 + Dex Modifier + Con Modifier. 
  • Monk Unarmored Defense: 10 + Dex Modifier + Wis Modifier. 

As you can see, these just let you add an additional modifier on top of the normal calculation for unarmored characters. These specific calculations use scores that are typically high priorities for the classes.

The draconic bloodline sorcerer also has a sort of variant to this feature called Draconic Resilience. On top of other abilities, this sorcerous origin allows the character to calculate their unarmored AC as the following: 13 + Dex Modifier.

Spells. It would be insane to list every spell or magical effect that deals with AC, but there are a couple that come to mind. The spells listed below specifically set a character’s AC, but there are many more that can increase AC.

  • Mage Armor. This excellent 1st level spell in the sorcerer and wizard spell lists allows you to set a creature’s base AC at 13 + their Dex Modifier, so long as they’re not wearing armor. This is commonly used by both wizards and sorcerers to increase their own AC. (Warlocks also gain the ability to cast this on themselves without burning spell slots by taking the Armor of Shadows eldritch invocation.)
  • Barkskin. A 2nd level spell in the spell lists of druids, rangers, and nature domain clerics, this spell lets you touch a creature and prevent their AC from being any lower than 16, regardless of the armor they’re wearing. This is great for stopping any adverse effects that could lower AC, but it can also be used as a buff for a character with a lower base AC.

What Improves my Armor Class in DnD 5e?  

So there are plenty of ways to set our AC, but how do we improve it? Well, there are plenty of ways we can boost AC. Features, spells, items, and more have the ability to make you harder to hit.

Using these abilities wisely will allow you to jump around the battlefield mostly unscathed.

Before we get into the things you can add to your character to improve your AC, the most important thing is to simply increase your ability scores. A character with natural armor or heavy armor won’t see any benefit here, but most armor calculations are based on modifiers.

Specifically, increasing your dexterity score, and therefore your dexterity modifier, is a surefire way to boost up your AC in most cases.

When it comes time to take an ASI, consider how often you’ve been getting hit, and if you should be focusing on the ability score that governs your armor.

Features

There are a couple different varieties of features. We have class and subclass features that you get at certain levels in a class. There are racial features, which you’ll get upon building your character.

Then, there are feats. When we take ASIs, we have the option to pick up feats, features that represent a specified bit of training outside of what your class offers.

Now, we can’t list every feature that has to do with AC, but be sure to examine the race, classes and subclasses you’re considering for any mention of armor class. Below are some of the most iconic options available.

Fighting Style. This feature is part of the class features for fighters, rangers, and paladins. Anyone that takes the Fighting Initiate feat can also choose a fighting style.  A few of the fighting styles provide a boost to AC. The defense fighting style gives you a +1 to AC while wearing armor.

Battlemaster Maneuvers. The bait and switch maneuver and the evasive footwork maneuver both allow you to increase your AC by the number you roll with your superiority die. That’s as much as a d12 bonus to AC!

Bladesong. The core feature of the bladesinging wizard. While it’s active you get to add your Intelligence modifier to your AC, no matter what your base AC calculation is. Since intelligence is the most important ability for a wizard, this is likely going to be a pretty solid boost.

Wild Shape. The druid’s wild shape ability allows them to take the form of a beast. One of the many benefits to this is that they take on the AC of the creature they form into. 

Artificer Infusions. The artificer has two infusions that boost AC. They can give an armor Enhanced Defense or turn a shield into a Repulsion Shield. Both options give a +1 to the wearer’s armor class.

Blade Flourish. The college of swords bard can add their bardic inspiration die to their AC when they make use of their defensive flourish.

Defensive Duelist. This feat is excellent for any characters with a minimum dexterity of 13 who uses a finesse weapon. In other words, a rogue. The feat let’s you use your reaction to add your proficiency bonus to your AC when you are attacked.

Dual Wielder. This feat gives you a +1 to AC while wielding a weapon in each hand, along with other abilities.

Medium Armor Master. This feat sets the max dex bonus to medium armor at +3 instead of +2. 

Spells

While there are plenty of spells that make you harder to hit in some way, there are only a few that specifically modify your AC.

Shield (Spell). This is a reactionary spell that gives you the caster a +5 to AC against the triggering attack and until the start of your next turn.

Shield of Faith. A concentration spell lasting up to 10 minutes which gives a creature of your choice +2 to AC for the duration.

Haste. Gives a creature a +2 to bonus to AC for up to 1 minute (again, concentration). It also has the added effect of doubling the target’s speed and giving them an extra action each turn which they can use to Attack, Dash, Disengage, Hide, or Use an Object. 

Items

Naturally, there are items, both magical and nonmagical, which increase a character’s AC.

Shield (Equipment). Perhaps the most obvious. Wielding a normal shield gives a creature a +2 to AC. 

Black Dragon Mask. This legendary wondrous item lets you add your charisma modifier to AC while you’re wearing no armor.

Magic Armor. This ever-so-vague improved armor can give you anywhere from +1 to +3. Magic armor can be any type of armor, so the base calculation is that of the armor type. You then just take the bonus and smile.

Arrow Catching Shield. This shield gives you a +2 to your AC against ranged attacks on top of the normal AC bonus a shield provides. 

Cloak of Protection. This cloak gives you a +1 to AC along with a +1 to your saving throws.You can gain this effect on top of your normal armor. (Although, you might want to wear it under your armor for practical reasons.)

For a full list of magic items that provide boosts to AC, check out this link to DNDBeyond. Don’t worry, I’ve set the search parameters to make your life easy. 

Other Methods

I’m going to say something that will sound very stupid. Increasing your AC isn’t the only way to improve your Armor Class. Let it sink in. Your AC is a number, but the concept of an armor class is how hard you are to hit.

You could also consider it as being “how often you’re going to take damage”. The following are just methods that will keep you taking the least amount of damage possible.

Disadvantage. Giving your foes disadvantage is similar to giving you a +4 to AC. I won’t go into the math, but I talk about this a bit in my article on the Great Weapon Master feat. It has a lot to do with statistics. Basically, they’re rolling much lower numbers all the time, and that makes it harder to hit you.

Resistances / Immunities. Resistances are key to not taking as much damage, since they half the damage of the specified type. Barbarians pick up a slew of resistances so that even when they do take hits they’re taking an impressively smaller amount of damage. You could almost say that having a resistance doubles your AC, since it has the same effect of being hit half the time.

Dodging / Moving Wisely. Dodge is a specific action that imposes disadvantage on all attacks made against you until the next turn. So we know why that’s great.

To add on to that, being a wise tactician and staying out of reach is quite simply the best way to avoid being hit. This is why monks and rogues tend not to need high ACs to get into the thick of the battle.

What is a Good AC for a level 1 player?  

It’s the question on everyone’s mind when they start playing. Quite simply put, don’t worry about it. Focus on making a fun character for you.

Nah I’m just kidding, let’s talk numbers.

The BEST AC a level 1 player can have without any bonuses from spells or magical items is 22.

That’s rewarded to a barbarian with a 20 in dexterity and a 20 in constitution who is wielding a shield. Monks don’t have shield proficiency, otherwise they’d be here as well. Frankly, this is an insane goal, and limits the weapon usage of a barbarian unless they also have a high strength score.

We shouldn’t be betting on good rolls when making a character, which is why I like to use the standard set of ability scores (15,14,13,12,10, and 8) when talking about building a character.

If you get a +2 and a +1 through your racial ability score increases, your max abilities are looking like a 17 and a 15. The modifiers for those would be +3 and +2 respectively. You could also have two 16s and have two +3 modifiers, which is pretty optimal. 

In this case, a monk is looking at a 16 AC since wisdom and dexterity are their primary ability scores. Barbarians are probably a bit lower, somewhere around a 14 or a 15 AC, since they should also be focusing on a high strength. 

Characters that wear armor can also look forward to somewhere between a 14 and 16 AC. Those who get chain mail as part of their starting equipment see an automatic 16, while others will need a healthy dex score to get there. 

Realistically, the ideal AC for each class is entirely dependent on their starting equipment and character build.

  • Artificer; AC 16 – The best option is to go with scale mail (14 + Dex mod max 2) which only has to mean a dex score of 14. 
  • Barbarian; AC 14 – They don’t need a high AC to stay durable, so a 14 is good enough. Ability score priority should typically be Strength > Constitution > Dexterity. 
  • Bard; AC 13 – Start off with leather armor and dexterity should be the second highest ability at around 14 or 15.
  • Cleric; AC 16 – The medium armor (scale mail) or heavy armor (chain mail) options both easily set you here with little focus on dexterity.
  • Druid; AC 12 – Druids can hang in there with low AC via leather armor until they start wild shaping into better options.
  • Fighter; AC 16 or AC 14 – Fighters can choose chain mail or leather armor. Typically, a strength based fighter will take the heavy armor option while a dexterity fighter will go light with a dex modifier of +3.
  • Monk; AC 16See Above. Unarmored defense with high dex and wis.
  • Paladin; AC 16 – Paladins start off with chain mail. 
  • Ranger; AC 14 – While a strength focused ranger can go higher with scale mail, the best option is a light armor dec ranger.
  • Rogue; AC 14/16 – Any rogue should have a high dex with their leather armor, but a smart build for good AC is taking a custom lineage or variant human to get the defensive duelist feat we talked about above. That 16 comes on line anytime you use your reaction.
  • Sorcerer / Wizard; AC 15 – Both of these classes are very mushy with very low hit points. Keeping them safe means having a decent dex modifier and casting mage armor whenever you enter battle. 
  • Warlock; AC 13 – Warlocks do start out with leather armor. They are also mushy though, so at level 2 they should pick up Armor of Shadows and try to get up to an AC of 15.