# Determining armor class 5e

In Dungeons and Dragons, armor class or AC is one of the main pillars of combat. It determines whether an attack hits or is deflected or dodged completely, and both the players and their enemies use it. It goes without saying that understanding it is a pivotal factor when understanding the game. In this article, let’s discuss what it is, how to calculate it, and some solid examples.

Contents

### What is Armor Class in Dnd 5e?

In Dungeons and Dragons Fifth Edition, Armor Class or AC is the value used to determine whether an attack hits. Used during an Attack Roll, should the resulting die roll be lower than the Target’s AC, the attack will not hit. Should the attack roll be higher than the AC, the attack will hit.

If you’re looking for more beginner guides, I’ll leave an interactive infographic below that can help you or a friend understand the game better. Be sure to check it out!

Basically, you can think of your AC as how hard it is to attack you. If you are wearing armor and your AC is high, you can think of it as having really great armor that deflect almost all attacks. If you are not wearing armor, you can think of it as being that quick and agile to be able to dodge all the attacks thrown at you.

During combat, everyone has to do an Attack Roll to determine whether their attack hits the intended target. This attack roll uses a d20 or a 20 sided-die, and the result of that roll will be held up against your overall AC.

To paint a better picture here’s an example:

Let’s say you have a character whose total AC comes up to 18, the attack roll has to match or exceed that value to hit you.

As you can see, Attack Rolls that come up to 18-19 or over will hit and those that are 17 and below will not. Take note that a nat20 or Natural 20 roll will result in having the attack hit no matter what your AC is.

A Nat20 or Natural 20 would mean that you scored a critical hit. Scoring a critical hit would mean automatically hitting the target, as well as doubling the damage dice you use for that attack. For an in-depth guide on scoring crits, click here.

You might get confused, though. AC is not necessarily Base AC, and there is still a calculation to be followed.

By the way, I work really hard on my content and it takes a long time to research and write all the information in the site. If you find it useful, please be sure to share and link back to articles for credit!

### How To Determine and Calculate Your Armor Class or AC in DnD 5e

In Dungeons and Dragons 5e, to determine your total AC during an attack roll, you need to add your Base AC and any modifiers that improve your AC. Once you have added your Base AC and other modifiers, that will be the AC used against the attack roll.

Determining the Base AC of your character is the first step to getting your AC. When starting the game, however, chances are you’ll be using your Base AC for the first few levels of the game.

A character’s Base AC means that it’s the AC before any added values. These added values can come in the form of spells, items, and special abilities. So that means your Base AC is either derived from your ability scores, armor, or class features.

I made a guide with an in-depth explanation of calculating Base AC. It has many examples and can shed some light to some of the finer details. You can find it by clicking here.

Here’s a table of Base AC calculations for your convenience:

Source

You can use this table to calculate and determine your Base AC. If you have anyone in your party that can increase your AC or any times or spells that can improve AC, you will be using this as a base.

Next will be adding the modifiers.

For example, there is a spell that can increase a character’s AC by +2 called Shield Of Faith (Not to be confused with an actual shield, we’ll get there later). If this character casts their Shield Of Faith spell on you, the formula used for your AC will now be:

AC = Base AC + Shield Of Faith spell

AC = Base AC + 2

You call spells, items, and other special abilities like these modifiers, and they’ll be the other variable when calculating for your AC.

So there you have it. To calculate your AC you need to know your Base Armor and AC modifiers. Once you know these, the formula will simply be:

AC= Base AC + AC Modifiers

### Examples For Different AC’s and Scenarios

Now that we know how to calculate your AC, let’s do some practical applications through different examples using the formula. But first, let’s establish a hypothetical character to use for all these.

Let’s call this character… Carl.

Now, let’s compute Carl’s AC with each of the Base AC computations.

For Breastplates, the Base AC computation is 14 + Dex Modifier (Max 2). This is directly from the Player’s Handbook on page 145. Basically, for Armor AC just follow the chart located there.

Next up is on the issue of shields. Standard reasoning would classify shields (not the spell) as armor, however, this is not exactly true with DnD 5e. In DnD 5e, you can add the shield to the Base AC and not count it as armor. Thanks to this, you can still use the Unarmored AC and the Unarmored Defense AC while still using a shield.

The shield will be our first modifier.

Unfortunately, however, shields will not take effect with Monks as they need both hands to function.

Since shields add a +2 to AC, this table will now be their overall AC with shields:

Now let’s include another modifier by adding Shield Of Faith (the spell into the equation). Again, this spell adds +2 to a character’s AC.

Now what to do with these values? Let’s see how they will apply to a combat situation where the attacker rolls a 16. Does the attack hit you, yes or no?

So, there you have it. We’ve calculated the Base AC and added the different AC modifiers. We’ve also applied the values to a practical example and took the result to show an accurate representation of what could happen given the different AC’s you get.

Something to take note, however, modifiers of the same nature do not stack. You can’t cast Shield Of Faith twice to double its effects.

This guide is an unofficial Fan Content permitted under the Fan Content Policy. Not approved/endorsed by Wizards. Portions of the materials used are property of Wizards of the Coast. ©Wizards of the Coast LLC.

Here are the infographics I promised. Feel free to swipe left or right!

Here’s one you can save and share with friends!

Sours: https://worldbuildersjunction.com/what-is-armor-class-in-dnd-5e-how-to-calculate-determine-ac/

## Mechanic Overview: Armor Class 5e

### What is Armor Class?

In 5th Edition, Armor Class (AC) is one of the most important aspects of any character because it determines how easily they can be hit. While it is specifically called “armor” class, a creature’s AC does not always entirely depend on how much armor a creature is wearing. A high AC can mean that a creature is particularly dexterous or that they can use magic to defend themselves.

There are a number of things that can increase a character’s AC, a few of which being armor, magic items, class features, and racial traits. In this Mechanic Overview, we will be covering the basics of AC, and how it interacts with other aspects of D&D’s 5th Edition.

### How does AC work in 5e?

When making an attack against a creature, if the attacker meets the defender’s AC the attack will hit. When making a Saving Throw, Armor Class does not affect the outcome of the roll.

### How do you calculate Armor Class in 5e?

When unarmored, your base Armor Class is 10 + Dexterity modifier. If you have a spell, item, feat, or racial trait that affects your Armor Class then the calculation will change.

The two most common ways to increase AC are to pump your Dexterity modifier (if you’re not wearing heavy armor) or to equip better armor. Below are some examples of different ways to increase AC, these options focus mainly on the Basic Rules, though some examples are given from other sources

### Armor

Armor is one of the most common ways to increase Armor Class in 5e. A character’s ability to wear armor directly ties to the class they take, though their ability scores and any feats they have also come into play.

Below is a table of the different types of non-magical armor that can be found in D&D 5e, before choosing to wear a certain type of armor, make sure that your class has proficiency in it, and that you meet any other requirements such as the minimum STR requirement for Heavy Armor and only being able to equip non-metal armor for Druids.

 Armor Cost Armor Class (AC) Strength Stealth Weight Light Armor Padded 5 gp 11 + Dex modifier — Disadvantage 8 lb. Leather 10 gp 11 + Dex modifier — — 10 lb. Studded leather 45 gp 12 + Dex modifier — — 13 lb. Medium Armor Hide 10 gp 12 + Dex modifier (max 2) — — 12 lb. Chain shirt 50 gp 13 + Dex modifier (max 2) — — 20 lb. Scale mail 50 gp 14 + Dex modifier (max 2) — Disadvantage 45 lb. Breastplate 400 gp 14 + Dex modifier (max 2) — — 20 lb. Half plate 750 gp 15 + Dex modifier (max 2) — Disadvantage 40 lb. Heavy Armor Ring mail 30 gp 14 — Disadvantage 40 lb. Chain mail 75 gp 16 Str 13 Disadvantage 55 lb. Splint 200 gp 17 Str 15 Disadvantage 60 lb. Plate 1,500 gp 18 Str 15 Disadvantage 65 lb. Shield Shield 10 gp 2 — — 6 lb.

### Class Features

Some classes gain the ability to increase their base AC:

• Monk: Unarmored Defense – Base AC = 10 + your Dexterity modifier + your Wisdom modifier
• Barbarian: Unarmored Defense – Base AC = 10 + your Dexterity modifier + your Constitution modifier
• Artificer Infusion: Enhanced Defense – This infusion allows you to increase the AC of a shield or suit of armor by 1. At 10th level, this bonus becomes +2.

There are other subclasses that can boost AC because of class features:

• Forge Domain Cleric: Soul of the Forge – Gain a +1 bonus to AC when wearing heavy armor.

### Magic Items

While magic items are rare and expensive, there are quite a few that can boost your AC. Some examples are below:

• Armor +X – +1/2/3 AC
• Arrow-Catching Shield – +2 AC against ranged attacks, among other effects
• Cloak of Protection – +1 AC and to all saving throws
• Demon Armor – +1 AC, among other effects
• Dragon Scale Mail – +1 AC, among other effects
• Dwarven Plate – +2 AC, among other effects
• Elven Chain – +1 AC, among other effects
• Glamoured Studded Leather – +1 AC, among other effects
• Ioun Stone (Protection) – +1 AC
• Ring of Protection – +1 AC and to all saving throws
• Shield +1/2/3 – +3/4/5 AC (because shields grant +2 AC, the +1 shield will grant +3 AC and so on)
• Staff of Power – +2 AC and to all saving throws, among other effects

### Racial Traits

Not many races give an inherent bonus to AC because of how strong an AC bonus at 1st-level tends to be. Some races that were introduced outside of the core sources that boost AC are:

• Tortle: Natural Armor – Base AC increases to 17 and can use Shell Defense to gain +4 to AC, among other effects.
• Warforged: Integrated Protection: – +1 AC

### Feats

We wrote an entire article on 5e feats so if you are looking for an in-depth look at them, that is where you can find it. Below are the feats that directly and indirectly impact AC:

• Dragon Hide – Base AC is 13 + your Dexterity modifier
• Heavily Armored – Gain proficiency with heavy armor
• Lightly Armored – Gain proficiency with light armor
• Medium Armor Master – Add 3, rather than 2, to your AC if you have a Dexterity of 16 or higher.
• Moderately Armored – Gain proficiency with medium armor and shields
• Shield Master – You can add your shield’s AC bonus to any Dexterity saving throw you make against a spell or other harmful effect that targets only you

### Spells

Because of the nature of the D&D 5e system, a lot of spells result in providing advantage or disadvantage to attacks, or resistance to a certain damage type. That said, there are a number of spells that can help with raising AC. Though none of these are permanent, some last longer than others:

• Barkskin: 1-hour duration – AC can’t be less than 16
• Ceremony (Wedding): 7 days duration – +2 AC while both creatures are within 30ft of each other
• Haste: 1-minute duration – +2 to AC, among other effects
• Mage Armor: 8-hour duration – Base AC becomes 13 + Dexterity Modifier
• Polymorph/True Polymorph: 1-hour duration – Creature adapts the AC of the creature it was turned into
• Shield of Faith: 10-minute duration – +2 to AC
• Tasha’s Otherworldly Guise: 1-minute duration – +2 AC, among other effects
• Warding Bond: 1-hour duration – +1 AC, among other effects

### Cover

One of the easiest ways to increase your armor class that is commonly overlooked is by using cover. Using the environment to your advantage grants the bonuses listed below:

• Half cover: +2 AC – A target has half cover if an obstacle blocks at least half of its body. The obstacle might be a low wall, a large piece of furniture, a narrow tree trunk, or a creature, whether that creature is an enemy or a friend.
• Three-quarters cover: +5 AC – A target has three-quarters cover if about three-quarters of it is covered by an obstacle. The obstacle might be a portcullis, an arrow slit, or a thick tree trunk.
• Total cover – Can’t be targeted directly by an attack or a spell, although some spells can reach such a target by including it in an area of effect. A target has total cover if it is completely concealed by an obstacle.

### Why doesn’t AC automatically increase with levels?

AC in D&D 5e doesn’t increase much above the low 20s and can be reached by PCs and NPCs at low levels. For example, a 1st-level Paladin wearing plate mail and wielding a shield has an AC of 20. An Adult Black Dragon, which is a challenge rating 17, only has an AC of 19. What gives?

D&D 5e is built around a system called “Bounded Accuracy” which locks “target numbers” in the game, such as Armor Class and the Difficulty Class, to levels that are reasonable to achieve at any level.

Under bounded accuracy, you won’t see these targets increase above a certain ceiling as characters progress. Instead, these targets remain fairly static, only ever reaching between 20 and 30.

“But” you may ask, “as characters level up, they face threats that have a higher chance to hit and can do more damage. Won’t that mean that characters facing these threats will die easier?”

Well, as characters level up, they are provided more tools that will allow them to deal with higher-level threats. These tools usually come in the form of a larger pool of hit points, more damage per round, or various other abilities they can use to swing the encounter in their favor.

Bounded accuracy suggests that there shouldn’t be a minimum level where you could ever hope to hit an Adult Black Dragon. Because an Adult Black Dragon’s AC is 19, they could be hit by a 1st-level character with a +5 to hit about 25% of the time.

Now, whether or not it’s reasonable for a party of 1st-level adventures to be able to defeat an Adult Black Dragon is another matter. While a party of new adventurers would likely fair poorly against such a great threat, if the PCs could rally a city against this dragon, or put it at a severe disadvantage, they actually may have a shot to kill it.

In short, Bounded Accuracy allows for a number of things, mainly:

• When characters level up, they actually get better at things. When you get +1 to an ability, you actually get 5% better at performing tasks in that area. In a system without Bounded Accuracy, these increases are necessary to provide even a basic level of competence to complete certain tasks.
• PCs that aren’t specialized in a certain field can still participate. A Barbarian with an 8 in Charisma can still be reasonably effective in social situations, even if they have a -1 modifier.
• It provides a consistent difficulty level for tasks. This allows DMs to improvise more effectively because they know that breaking down an iron door is a DC 17 Strength check, no matter what level the characters are.
• It expands the list of encounter options over time, it doesn’t limit them. Because the character’s AC doesn’t increase above levels that can be met by lower-level creatures, the pool of viable enemies that the party can face only expands over time.

### Conclusion

In short, AC is a simple enough mechanic on the surface. It allows new players to hop into the game easily, by telling them “if you hit this number, that creature takes damage”. But, when combined with the other mechanics in the 5e system, such as Advantage and Disadvantage, it still provides enough complexity and depth to be relevant to higher levels of play.

If you enjoyed our overview of the AC mechanic or would like to see other mechanics dissected in future posts leave us a comment below! Thanks for reading and remember, in the immortal words of Wayne Gretzky Michael Scott, “you miss 100% of the shots you don’t take”.

### Mike Bernier

Mike Bernier is the lead content writer and founder of Arcane Eye. Outside of writing for Arcane Eye, Mike spends most of his time playing games, hiking with his girlfriend, and tending the veritable jungle of houseplants that have invaded his house. He is the author of Escape from Mt. Balefor and The Heroes of Karatheon. Mike specializes in character creation guides for players, homebrewed mechanics and tips for DMs, and one-shots with unique settings and scenarios. Follow Mike on Twitter.

Sours: https://arcaneeye.com/players/armor-class-5e/

If you wear Medium Armor, you add your Dexterity modifier, to a maximum of +2, to the base number from your armor type to determine your Armor Class.

Furthermore, how do you determine DND armor class?

Here are some ways to calculate your base AC: Unarmored: 10 + your Dexterity modifier. Armored: Use the AC entry for the armor you're wearing (see PH, 145). For example, in leather armor, you calculate your AC as 11 + your Dexterity modifier, and in chain mail, your AC is simply 16.

Furthermore, how much AC does leather armor add? Armor Categories | Armor Statistics | Getting Into and Out of Armor

Light Armor
ArmorArmor Class (AC)Weight
Leather11 + Dex modifier10 lb.
Studded Leather12 + Dex modifier13 lb.
Medium Armor

Herein, how do you use armor class in D&D?

It's function hasn't changed: the better (higher) your Armour Class, the harder you are to hit. When an attack is made, the attacker rolls a 1d20 and adds their attack bonus; if the result equals or exceeds the target's Armour Class, the target is hit.

How does AC work in 5e?

AC is effectively the difficulty class (DC) for attack rolls and thus determines how hard you are to hit with melee and ranged attacks in combat. Armour and shields are components of your AC. AC is simply a measure of how hard it is to strike a figure in a way that does damage.

Explaining D\u0026D (badly) - How to calculate AC in 5th edition!

Sage Advice is a monthly column that gives official clarifications of D&D rules. It also sometimes provides reference documents to help your D&D game run smoothly. Despite its official status, Sage Advice doesn’t trump the rulings of a Dungeon Master; the answers and information provided here are meant to assist a DM in adjudicating the game.

If you have questions for a future installment of Sage Advice, please send them to [email protected], or reach me on Twitter (@JeremyECrawford), where I answer questions between installments of this column.

### Character Creation

How do you calculate a creature’s Armor Class (AC)? Chapter 1 of the Player’s Handbook (p. 14) describes how to determine AC, yet AC calculations generate questions frequently. That fact isn’t too surprising, given the number of ways the game gives you to change your AC!
Here are some ways to calculate your base AC:

• Unarmored: 10 + your Dexterity modifier.
• Armored: Use the AC entry for the armor you’re wearing (see PH, 145). For example, in leather armor, you calculate your AC as 11 + your Dexterity modifier, and in chain mail, your AC is simply 16.
• Unarmored Defense (Barbarian): 10 + your Dexterity modifier + your Constitution modifier.
• Unarmored Defense (Monk): 10 + your Dexterity modifier + your Wisdom modifier.
• Draconic Resilience (Sorcerer): 13 + your Dexterity modifier.
• Natural Armor: 10 + your Dexterity modifier + your natural armor bonus. This is a calculation method typically used only by monsters and NPCs, although it is also relevant to a druid or another character who assumes a form that has natural armor.

These methods—along with any others that give you a formula for calculating your AC—are mutually exclusive; you can benefit from only one at a time. If you have access to more than one, you pick which one to use. For example, if you’re a sorcerer/monk, you can use either Unarmored Defense or Draconic Resilience, not both. Similarly, a druid/barbarian who transforms into a beast form that has natural armor can use either the beast’s natural armor or Unarmored Defense (you aren’t considered to be wearing armor with natural armor).

What about a shield? A shield increases your AC by 2 while you use it. For example, if you’re unarmored and use a shield, your AC is 12 + your Dexterity modifier. Keep in mind that some AC calculations, such as a monk’s Unarmored Defense, prohibit the use of a shield.

Once you have your base AC, it can be temporarily modified by situational bonuses and penalties. For instance, having half cover gives you a +2 bonus to your AC, and three-quarters cover gives a +5 bonus. Spells sometimes modify AC as well. Shield of faith, for example, grants a target a +2 bonus to AC until the spell ends.

Magic items can also enhance your AC. Here are a few examples: +1 chain mail gives you an AC of 17, a ring of protection gives you a +1 bonus to AC no matter what you’re wearing, and bracers of defense grant you a +2 bonus to AC if you’re not wearing armor or using a shield.

### Spells

Does Unarmored Defense work with a spell like mage armor? Unarmored Defense doesn’t work with mage armor. You might be asking yourself, “Why don’t they work together? Mage armor specifies that it works on a creature who isn’t wearing armor.” It’s true that the target of mage armor must be unarmored, but mage armor gives you a new way to calculate your AC (13 + your Dexterity modifier) and is therefore incompatible with Unarmored Defense or any other feature that provides an AC calculation.

How does barkskin work with shields, cover, and other modifiers to AC? Barkskin specifies that your AC can’t be lower than 16 while you are affected by the spell. This means you effectively ignore any modifiers to your AC—including your Dexterity modifier, your armor, a shield, and cover—unless your AC is higher than 16. For example, if your AC is normally 14, it’s 16 while barkskin is on you. If your AC is 15 and you have half cover, your AC is 17; barkskin isn’t relevant in this case, because your AC is now higher than 16.

Can you extend the duration of armor of Agathys by gaining more temporary hit points? The spell is meant to work only as long as you have the temporary hit points that the spell grants. When those temporary hit points are gone, the spell is done.

Keep in mind that temporary hit points aren’t cumulative (see PH, 198). If you have temporary hit points and receive more of them, you don’t add them together, unless a game feature says you can. You decide which temporary hit points to keep. As an example, let’s say you’re a warlock with the Dark One’s Blessing feature, which gives you temporary hit points when you reduce a creature to 0 hit points. You currently have 2 temporary hit points from armor of Agathys, you just slew a monster, and your Dark One’s Blessing can now give you 4 temporary hit points. If you take those temporary hit points, they replace the ones from armor of Agathys and end that spell, so you might not want to take them and keep the spell going.

Do the temporary hit points from heroism accumulate each round? These temporary hit points aren’t cumulative. The spell would tell you if you were meant to add them together. At the start of each of your turns, the spell, effectively, refreshes the number of temporary hit points you have from it; if you lost some or all of the temporary hit points, the spell gives them back to you.

### Taking a Second Look at a Ruling

I’m constantly revisiting the rules of the game. As a DM, I use them in the games I run. As a designer and editor, I refer to them every week to ensure that future D&D books are on course. As the Sage, I consider them from different angles when new questions arrive in my inbox and on Twitter. This sometimes leads me to reconsider a ruling I’ve made.

In this installment of Sage Advice, there’s an example of me revisiting a ruling. On Twitter, I recently gave a different explanation for how barkskin works and, by extension, how shields work. What I said was based on the game’s text, but the text is sometimes inconsistent on how shields are treated. In my official ruling here in Sage Advice, I’ve decided to counter what I said on Twitter about barkskin and shields to go with a simpler explanation—one that is also supported by the text and that more closely aligns with our design intent.

In the Sage Advice Compendium below, I’ve also changed my ruling on the Savage Attacker feat, which I originally addressed in November 2015. The original ruling was simply off-base—I read the feat too fast—so I’ve fixed it.

The Sage Advice Compendium gathers every installment of Sage Advice in one PDF. It’s been updated to include this month’s questions and answers.

### Monster Manual Errata

We’ve updated the Monster Manual Errata file to more closely match the latest printing of the book. The PDF now includes an entry for the water elemental, and the kraken entry now reflects what’s in the book.

### Other Resources

Here are other D&D reference documents we’ve posted on this website.

Basic Rules for Dungeons & Dragons

D&D Spell List (version 1.01)

Monsters by Challenge Rating (version 1.0)

D&D Monsters by Type (version 1.0)

Magic Items by Rarity (version 1.0)

Conversions to 5th Edition D&D (version 1.0)

Character Sheets

Jeremy Crawford is the co-lead designer of fifth edition Dungeons & Dragons. He was the lead designer of the fifth edition Player’s Handbook and one of the leads on the Dungeon Master’s Guide. He has worked on many other D&D books since coming to Wizards of the Coast in 2007. You can reach him on Twitter (@JeremyECrawford).

## How To Calculate Armor Class (AC) In DnD 5E

When it comes to combat in any game, you typically want to hit with many attacks without getting hit yourself. Whether you want to dance over swords while singing “Can’t Touch This,” have arrows bounce off your rippling muscles, or stop a blade with your gleaming plate mail, in dungeons and dragons, we have something called Armor Class -often shortened to AC – which helps you do this very thing.

Now figuring out how to calculate AC is an excellent skill to have and is very easy! For any unarmored character/creature, start with 10, and add the Dexterity Modifier alongside any other bonuses. Simple! Armor is a little more tricky:

• Light armor and the mage armor spell, they change the 10 in that formula
• Medium armor however only adds up to +2 to your AC from Dexterity (+3 if you have the Medium Armor Master feat)
• Heavy armor ignores Dexterity altogether, be careful of Strength Requirements. If you don’t meet the Strength requirement listed for your chosen Heavy Armor, then your movement speed will be reduced by 10ft unless you’re a Dwarf.

Of course, there are features such as the Barbarian’s and Monk’s Unarmored Defense abilities that can also increase AC. However, such features typically tell you how to calculate AC. Some cases give you a flat AC number to use, such as the Tortle’s natural AC or the Barkskin spell. Other than that, you only need to keep track of magic items, magical effects, shields, and additional bonuses to AC.

Tip: AC calculations don’t stack! If you have two different ways of determining your AC, for example, a Tortle Barbarian, you would need to choose between the Tortle’s fixed 17 AC or the Barbarians Unarmored Defense formula. Bonuses to AC like shields and magic items will still apply unless the AC giving feature says otherwise.

Now that you know, I see a high AC build in your future. Good Luck, and don’t die!

Author
Samuel loves DnD and has been running campaigns over roll20 for over a year. He's quickly learned how best to run a campaign in that period of time. But if there's one thing he loves most about DnD, it's sharing an incredible experience with his friends online.
Sours: https://dicecove.com/how-to-calculate-armor-class/
What is Armor Class or AC (D\u0026D)

One of the bigger changes to the game in the new edition of Dungeons & Dragons concerns Armour Class.

It’s function hasn’t changed: the better (higher) your Armour Class, the harder you are to hit. When an attack is made, the attacker rolls a 1d20 and adds their attack bonus; if the result equals or exceeds the target’s Armour Class, the target is hit.

Although its function in the game hasn’t changed, it doesn’t just keep going up and up and up like in 3E and 4E. A major factor in the new edition’s design is Bounded Accuracy, which means that target numbers can’t change too much. Within the game, this translates to most Armour Classes being in the range of 10 to 20.

When a monster or character goes outside those ranges, you generally can assume there are magical items or spells involved, or the monster is special in some way. In the Basic Rules, the best Armour Class is 19, held by an adult dragon. The Hoard of the Dragon Queen Online Supplement has two monsters with an Armour Class of 20 – a helmed horror and a roper. Nothing in those documents gets better. Almost nothing in the Monster Manual exceeds 20.

This is, in many ways, similar to the original Dungeons & Dragons design, where monster Armour Classes were all in a very limited range: basically from 2 to 9. In those days, instead of providing a target number, they provided a chart reference; you’d cross-reference the Armour Class with the level or Hit Dice of the attacker to see what the target number was. Making Armour Class into the target number was one of the things the 3E designers got absolutely right. Historically, using a look-up chart for Armour Classes allowed non-linear progression of the target numbers, but that concept was largely abandoned by the time original D&D was printed.

With Bounded Accuracy in place, this has several implications to how Armour Class is calculated. Drawing on the terminology of previous editions, you have a Base Armour Class which then has several Armour Class Modifiers applied to it before you get the final result.

In 3E, your Base Armour Class was 10, and then everything else modified it: Armour, Shields, Dexterity, Spells, Amulets, Rings, and so on. In 4E, you also gained a bonus to it equal to half your level.

This is not how it works in 5E. Instead, Armour, Spells or Special Abilities provide you with a Base Armour Class, which is then modified by a very limited number of sources.

If your character has several ways of calculating their base armour class, you only use one method.

Here are a few examples of Base AC calculations:

• No Armour: Base AC = 10 + Dexterity modifier
• Leather Armour: Base AC = 11 + Dexterity modifier
• Chain Shirt: Base AC = 13 + Dexterity modifier (max +2)
• Plate Mail: Base AC = 18
• Mage Armour spell: Base AC = 13 + Dexterity modifier
• Barbarian Unarmoured Defense
ability: Base AC = 10 + Dexterity modifier + Constitution modifier
• Monk Unarmoured Defense ability: Base AC = 10 + Dexterity modifier + Wisdom modifier
• Sorcerer Draconic Resilience ability: Base AC = 13 + Dexterity modifier

Meanwhile, there are several ways of further modifying your Armour Class. A few examples of these

• Shield: +2 bonus to AC*
• Shield of Faith spell: +2 bonus to AC
• Shield spell: +5 bonus to AC
• Half Cover: +2 bonus to AC
• Three-Quarters Cover: +5 bonus to AC
• +1 Armour: +1 bonus to AC
• Ring of Protection: +1 bonus to AC; requires attunement
• Bracers of Defense: +3 bonus to AC when not wearing armour or using a shield; requires attunement
• Arrow Catching Shield: +1 bonus to AC against ranged attacks; requires attunement

There is at least one unusual exception to how AC is calculated:

• Barkskin spell: Your minimum AC is 16.

*: The description of shields is unusual as it says it modifiers your base AC, but for most intents and purposes you can just treat it as a regular modifier.

As you can see, a multiclass Barbarian/Monk does not get to add all of their Dexterity, Constitution and Wisdom modifiers to the Armour Class! They have three ways of calculating their base AC, but can only choose one. However, they can benefit from as many other bonuses to AC as they like.

All the other modifiers stack; they aren’t split into several types of modifier like in 3E. (The one exception is that you can’t benefit from the same effect twice; if two clerics cast Shield of Faith on you, you only get a +2 AC. Multiple copies of the same spell do not stack!)

So, why can’t you just apply modifier after modifier and end up with a fantastic Armour Class that requires a natural 20 to hit? Well, you can in limited circumstances. However, there are three major restrictions on increasing your AC.

The first is that there aren’t all that many ways of modifying AC. Although several magic items in the Dungeon Master’s Guide do so, it’s something that the designers kept an eye one. +1 magic armour is sort of hard to find, but +3 armour is rare and precious, and +5 armour? It doesn’t exist!

The second is attunement. Magic items that provide powerful effects (and most permanent items that affect major numbers on your character fit into that category) have the limitation of “requires attunement”. The rules state that a character may have a maximum of three items attuned to them, so you are limited in that sense as well.

The third is concentration. Ongoing spells that provide bonuses typically require the caster to concentrate on them. That means that the caster can’t have any other spells requiring concentration at the same time. One character could get the benefit from a few spellcasters all providing them with armour class bonuses from different spells, but that will be the exception and not the rule, and the rest of the party wouldn’t be benefitting. It should be noted that there are very few spells that provide a bonus to AC in any case.

Honestly, the best way of increasing your Armour Class? Get behind an arrow slit! They provide three-quarters cover. Unfortunately, dungeon designers typically don’t design their dungeons with arrow slits the characters can take advantage of…

The flip side of this is to consider the range of attack bonuses. Just taking a quick flip through the Basic DM Rules, I see attack bonuses in the range of +0 to +14 (crab to adult dragon), with most being in the range of +3 to +7. A player character can probably expect at high levels to get a regular attack bonus of +12, assuming a 20 in the appropriate ability score, the full +6 proficiency bonus and a +1 weapon. Spells, items and abilities may push it a few points higher.

So, that’s a brief tour of how Armour Class works in the new edition. If you’d like to compare how AC worked in previous editions, I have articles on Armour Class in Original D&D and AD&D, AD&D 2E and D&D 3E. This is unlikely to be my last word on the topic, as my analyses are anywhere but complete!

ArmourBase ACType
Leather11 + Dex modifierlight
Studded leather12 + Dex modifierlight
Hide12 + Dex modifier (max 2)medium
Chain shirt13 + Dex modifier (max 2)medium
Scale mail14 + Dex modifier (max 2)medium, stealth disadvantage
Breastplate14 + Dex modifier (max 2)medium
Half plate15 + Dex modifier (max 2)medium, stealth disadvantage
Chain mail16heavy, stealth disadvantage, Str 13
Shield+2modifies Base AC

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Sours: https://merricb.com/2014/09/13/armour-class-in-dungeons-dragons-5e/

### Now discussing:

Everything in Dungeons & Dragons has an AC or Armor Class. This number indicates how difficult that thing is to harm. Determining AC for players is relatively easy, however, how do you know the AC of, say, a door? And how do you describe a missed attack in a way that isn’t repetitive or boring? That’s where this quick guide comes in!

How do you determine AC in Dungeons & Dragons 5e?

• To determine is an attack “hits,” roll a d20 and add any modifiers if the number is equal to or greater than the creature’s armor class, the attack hits.
• To determine your players or NPCs base Armor Class, you simply add 10 + their Dexterity modifier.
• To determine the AC of objects, decide how difficult they are to break. A wooden door might have an Armor Class of 11, but a metal chest will have an AC of 14.

The base AC of your players determines how difficult they are to hit. When rolling an attack, if the number rolled plus any modifiers is equal to or greater than the armor class, the attack hits.

For flavor in your descriptions, you can attribute a missed attack to either the player’s dexterity or armor, but either way, the number that determines AC comes from the player’s Dexterity modifier.

The higher the player’s AC, the more difficult it is for enemies to land a hit on them. Most players will not start with a high AC, but there are several ways for Players or NPCs to raise their AC.

### Armor and Shields

Armor and shields both serve to increase AC, but players must have proficiency with the armor they are wearing or the will suffer penalties to ability checks.

Most players think they can jump into whatever set of armor they want and start fighting like normal, but it takes a lot of training to be able to fight in armor. Class determines proficiency, and if players do not have proficiency in the armor they are wearing, then the following penalties apply:

• Disadvantage on Strength & Dexterity Ability Checks
• Disadvantage on Strength & Dex Saving Throws
• Disadvantage on Attacks that relies on Strength or Dexterity
• Cannot cast Spells

Unlike armor, anyone can use a shield. A shield adds +2 to Armor Class and does not pose any disadvantages other than it requires one hand to wield. This means that if a weapon requires two hands to use, then the player cannot wield the shield and use that weapon at the same time.

Likewise, if a spell requires two hands to cast, the player must first put away or drop the shield before casting, lower their armor class by 2.

### Selling Armor & Weapons

As your party levels up and gains gold, they will likely want to upgrade their weapons and armor. This means they will be looking to sell their old gear or maybe even sell the armor and weapons they come across on their adventures.

A good rule of thumb is that undamaged armor and weapons used by players will sell for half or less of their cost (see chart below).

### Pulling Armor Off Dead Enemies

Perhaps your party likes to save money by trying to salvage armor from dead enemies. While this might seem economical, in real life it is unlikely that such items would actually fit.

Unlike weapons that are universal in size, armor is fitted to the individual. This means one person’s armor is not likely to fit another person perfectly. While the armor will still offer the same level of protection, ill-fitting armor is likely to impose disadvantages.

If a player chooses to use armor that does not fit them, they have the same disadvantages as if they were not proficient in the armor type until they get it altered. This ruling allows players to save money (alternations are far cheaper than buying the set of the armor itself) but maintains a logical sense of reality.

### The Armor Class of Objects

Most often your players will be trying to hit enemies. Each monster stat box will include the monster’s AC. However, there are times when your players will be aiming for inanimate objects which do not have a dexterity modifier. How do you determine the AC of objects?

While AC can refer to how quickly something can dodge out of the way of attacks, it can also relate to how hefty something is. Objects that are easily broken will have a low AC, while sturdy objects will have a much higher AC. See the chart below for a helpful reference.

### Describing Missed Attacks

When your players or monsters miss an attack, instead of just saying “They miss you,” and moving on, try using some of these phrases:

• The attack glances off your armor leaving a long scratch on the metal
• At the last moment, you raise your shield, forcing the attack to bounce off harmlessly
• You fire your arrow, it hits just where you aimed, but you watch as it shatters against the iron scales of the beast
• You raise your sword and bring it down in an arc strike, but the enemy jumps nimby over your attack, avoiding it
• The monster lunges at you, you hold up your sword, catching it before its jaws sink into your neck. It snaps at you madly, unable to reach you before you throw it off

Remember, even missed attacks can be opportunities for epic battle descriptions! Make them just as interesting as your successful attacks if you want to keep your players engaged.

Everything has an Armor class. AC is one of the most useful machines in the game and you can use it in a variety of ways to add depth and flavor to your campaign.

Now that you know the ins and out of Armor Class, you should always know what hits and what doesn’t.

Until next time,

-Halfling Hannah

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