What is the highest possible AC?

Question

Assuming you are level 20, and have access to any magic item, how high can you get AC (permanently or for a set duration)?

Constraints:

Magic items are those on the tables in the D&D 5th Edition DMG.
Spells, skills, feats and abilities available to a player character are eligible for use/consideration.

No buffing, no other help from an ally. This AC is achieved by a single player character.

Extra clarification: Time and magic items are limited to practical use. Think of it as a game plan for a campaign with a very generous DM.

Answer 1

Under unusual circumstances, it is possible to get an AC of 49

• Highest permanent AC: 31
• Highest combat-ready AC: 35
• Highest the-stars-aligned AC: 49

Permanent AC with Magic Armor, no other Magic Items: 27

There are actually several ways to achieve this.

• Barbarian 20
  • 22: Unarmored Defense = 10 + 5 (20 DEX) + 7 (24 CON)
  • +5: +3 Shield

    NOTE: Barbarian 20 precludes several options that require levels in other classes

• Heavy Armor
  • 21: +3 Plate Mail
  • +1: Defense Fighting Style (Fighter 1 or Ranger 2 or Paladin 2)
  • +5: +3 Shield
• Medium Armor
  • 18: +3 Half-Plate
  • +3: 16 DEX or better and Medium Armor Master Feat
  • +1: Defense Fighting Style (Fighter 1 or Ranger 2 or Paladin 2)
  • +5: +3 Shield

Things that don't work:

• Light Armor: 26
  • 15: +3 Studded Leather
  • +5: 20 DEX
  • +1: Defense Fighting Style (Fighter 1 or Ranger 2 or Paladin 2)
  • +5: +3 Shield
• Robe of the Archmagi: 25
  • 15: Robe of the Archmagi (Wizard, Sorcerer, or Warlock 1)
  • +5: 20 DEX
  • +5: +3 Shield
• Monk: 20
  • 20: Unarmored Defense = 10 + 5 (20 DEX) + 5 (20 WIS)
  • +0: Precludes shield

Adding Magic Items with Ongoing Effects (Except ones that permanently raise ability scores): 31

• +2: Staff of Power (Wizard, Sorcerer, or Warlock 1)
• +2: Choose two out of Ring of Protection, Cloak of Protection, Ioun Stone - Protection

NOTE: The Defender, because of the way it works, is considered (and rejected) as a Situational AC Boost.

Adding Combat Buffs - Consumable Magic Items and Spells: 35

• +2: Potion of Speed (effect of Haste spell, no Concentration)
• +2: Shield of Faith (Cleric 1 or Paladin 2, Concentration)

Adding Situational AC Boosts: 49

• +5: 3/4 Cover
• +4: Multiattack Defense (Ranger 7, triggered by getting hit, active for rest of attacking creature's turn)
• +5: Shield (Wizard 1, reaction to being hit, active until your next turn)

A note on the Defender: The Defender and Staff of Power are both weapons that can provide a significant AC boost. I think most characters with the choice would choose the Staff of Power. In hand it is always on and also has a +2 attack or spell DC bonus. The Defender is not in effect during any round you do not attack, including a surprise round or a round in which you Disengage or Dodge, and going max AC leaves no bonus for the attack roll. Importantly for this question, hiding behind 3/4 cover pretty much means you are not attacking, and therefore cannot shift +3 to AC. If the Defender replaced the Staff of Power and chose not to hide behind 3/4 cover, the highest AC would be 45.

Bonus Questions: What's the lowest level at which I could achieve this?

Because this doesn't rely on crazy stats, it can be achieved at a fairly low level. We have a choice between a Heavy and a Medium Armor build. Using the Medium Armor build obviates the need for Heavy Armor Proficiency (which would require a feat or 1st level in Fighter or Paladin).

Minimum Stats (easily achievable at 1st level using the default array with any PH race):

• DEX 16
• INT 13 (Wizard multiclass)
• WIS 13 (Ranger and Cleric multiclass)

Feat:

• Medium Armor Master - taken at Ranger 4, or at 1st level as a Variant Human

Minimum class level requirements:

• Ranger 7 / Wizard 1 / Cleric 1

Important Caveats

I have assumed that ability scores max out at 20 unless a class feature says otherwise. If abilities go above 20, where do they stop? I have chosen to disregard two possible ways in which characters can get ability scores over 20:

1. Even without magic items, Epic Boons can be used to continue to improve abilities to 30 (DMG 230), while the characters remain "20th level" characters. Given enough time, assume all 30s.
2. There are several magic items that give permanent ability boosts. The only ones worth considering here are the Tomes and Manuals which give +2 to the relevant ability but also increase the ability maximum by 2. Although, once used, they become blank for a century, there is nothing in these manuals that suggest they are unique or that they can't benefit a character multiple times. How high can your ability scores go? Per RAW and RAI, the answer to Can I increase an ability score above 30? is NO.

In either case, we no longer need Barbarian 20 for CON 24. Barbarian 1 gets access to Unarmored Defense, time/magic gets us DEX 30, CON 30, and multiclassing is possible. Highest the-stars-aligned AC becomes 57. I think this violates the spirit of the question however.

Answer 2

Potentially Highest Achievable Armor Class

Character Class: Barbarian using Unarmored Defense & some magic items

• AC 30(33) appears to be a theoretical max for "walking around" AC¹

• AC 42(45) appears to be a theoretical max for a brief duration¹

+1 Ring of Protection (1)(attuned)¹
+1 Cloak of Protection(attuned)¹
Dexterity = 22²
Constitution = 24³
Magical shield: +3(attunement not required)
Defender sword(Legendary)⁴
Feat: Defensive Duelist ⁵

¹ You need to attune the cloak and the ring. Based on Sage Advice from Jeremy Crawford, 21 Sept 2015, you can't attune two Rings of Protection.
² Max Dex is 20, 22 with a Manual of Quickness in Action
³ the +4 added to the usual cap of 20 is unique to lvl 20 Barbarians; the 4 extra points come with the capstone "Primal Champion" feature
⁴ Defender sword requires attunement; you have to be in combat and choose on the first attack of your turn to get the sword bonus
⁵ If using a finesse weapon (a match with high dexterity on this character) add the proficiency bonus (+6) to AC for one attack against you (p. 165 PHB). This is treated separately in calculations.

Calculation

Permanent/walking around armor class = 30(33)⁴ \begin{array}{rl} 10 & \text{(base)}\\ +13 &\text{(+6 Dex, +7 Con)}\\ +5 &\text{(+2 shield, +3 magic)}\\ +2 &\text{(ring and cloak)}\\ \hline = 30\\ +3 &\text{(when using all bonuses on sword for defense)}\\ \hline = 33 \end{array}

Temporary #1: If you are behind Half Cover: +2 bonus to the above 32(35)⁴
Temporary #2: If you are behind Three-Quarters Cover, +5 bonus to the above. 35(38)⁴

• Note, you are either behind 1/2 or 3/4 cover; you can't stack those.

Temporary #3: Magic

• If the Barbarian can read a magical scroll (For the duration of the spell)

  • Cast from a scroll "Shield of Faith spell" add +2 bonus to the above.

  • Cast from a scroll "Shield" spell, you'd add +5 bonus to the above.

These spells should stack. From @Ethan's suggestion: the Magic Initiate Feat could supply the Shield Spell once per day and avoid having to use a scroll in combat.

The effects of different spells add together while the durations of those spells overlap. The effects of the same spell cast multiple times don’t combine, however. Instead, the most potent effect—such as the highest bonus—from those castings applies while their durations overlap. (Basic Rules p. 81)

It looks like the max with 3/4 cover and a shield spell is 42(45)⁴

---

Multi Classing: Barbarian MC loses the Constitution boost to 24 (Capstone).

If the Barbarian multi-classes, subtract 1 from his Constitution bonus; we'll assume a manual of Bodily Health (22 Con). He could take 1 level in Wizard and cast the Shield spell.

The "walking around" AC would drop to 29(32)⁴, his temporary could add +5 from that spell 35(37)⁴ and get could as high as 41(44)⁴ if all of the necessary conditions noted above are met.

---

Defensive Duelist Feat

With three creatures attacking you, you only get this +6 boost for one attack, but if you are fighting just one creature, this provides an AC boost of 6 from that feat. (Occasional 39/51 AC is thus possible if all other conditions are met). How to combine that with 3/4 cover becomes a tactical question; most of the time won't apply. The more likely benefit of this feat is a 33/46 theoretical max.

---

Is there a hard cap on ability scores, once the magical manuals that allow a PC to raise an ability score above 20 are made available to player characters?

• A hard cap at 24 is implied by the descriptions of two artifacts

The Book of Exalted Deeds and The Book of Vile Darkness, both of which allow ability increases beyond 20 but with a cap at 24. (DMG p. 222 and 223).

• If there isn't really a hard cap, then the answer provided by Miniman --"how many manuals can you get your hands on?" -- represents how high your armor class can go: no limit.

Answer 3

With the conditions you've set, you can have infinite AC. Just buy an infinite number of Manuals of Quickness of Action, and your AC will be limited only by the time it takes to use them.

Answer 4

The Highest Possible AC is 69

• Permanent AC: 33
• Combat AC: 39
• One-attack AC with the same build: 58 (65 max)
• One-attack AC with specialized build: 61 (69 max)

Permanent AC with no Magic Items: 22

• Fighter 1 [for Defense Fighting Style]
• Cleric 6 [for heavy armor proficiency and Soul of the Forge]

18: Plate Armor
+2: Shield
+1: Defense Fighting Style
+1: Soul of the Forge

Adding Magic Items and Other Rewards: 33

• Wizard 1 [for magic item prerequisites]

+3: Magic Armor
+3: Magic Shield
+2: Staff of Power
+2: Choose two out of Ring of Protection, Cloak of Protection, Ioun Stone - Protection
+1: Blessing of Protection

Adding Consumable Magic Items and Spells: 39

• has Cleric (Forge) 1 [for Shield of Faith]
• Wizard (War Magic 10) [for Durable Magic]

+2: Potion of Speed
+2: Shield of Faith
+2: Durable Magic

Expected AC for One Attack: 61 (69 max)

• has Wizard (War Magic) 2 [for shield and Arcane Deflection]
• has Cleric 4 [for 1 feat]
  • Martial Adept [for Evasive Footwork]
• replace Wizard 3-10 and Fighter 1 with Ranger (Hunter) 7 [for Defense Fighting Style and Multiattack Defense]
• Bard (College of Swords) 5 [for Defensive Flourish and Bardic Inspiration (d8)]

+5: 3/4 cover
+5: shield
+2: Arcane Deflection
+2: Multiattack Defense [replaced Durable Magic]
+1d8: Defensive Flourish
+1d6: Evasive Footwork

Note: without replacing the Wizard and Fighter levels (if you want the same build as highest combat-ready AC) you will only have a d6 Defensive Flourish and miss out on Multiattack Defense resulting in an Expected -3 AC (-4 max)

Note 2: after attacking to activate Defensive Flourish, the PC must drop his finesse weapon and draw the Staff of Power with his/her free object interaction. If your GM rules that dropping the finesse weapon serves as your free object interaction (a ruling I haven't seen before, but is possible), then you will lose +2 AC for the purposes of one-attack AC

What about Manuals and Tomes?

I assumed a maximum of 20 for each ability score because the number of magic items and other rewards is already very restrictive. This clause from the question prompted this:

Time and magic items are limited to practical use

Collecting a bunch of Very Rare magical books on top of the items already needed is impractical (as is waiting for them to refresh their magic). If you want to include them, you will have to change the entire build to account for Unarmored Defense, Bladesong, and the Dual Wielder feat

• (Barbarian OR Monk 1/Wizard 2/Ranger 7/[Bard 10/Martial Adept OR Bard 5/Fighter 3])

which gives you these numbers before tomes and manuals:

• Permanent AC: 31
• Combat AC: 35
• One-attack AC: 58 (65 max)

Then just add 1 to each metric for each book read (up to a maximum of 5 each) among:

• Manual of Quickness of Action
• Tome of Clear Thought
• Manual of Bodily Health OR Tome of Understanding

This brings the theoretical maximum to:

• Permanent AC: 46
• Combat AC: 50
• One-attack AC: 73 (80 max)

Answer 5

Alright. Let's work this out, since my friends and I have as well.

High Elf Barbarian 1 (Let's assume, for all intents and purposes, you started with maxed stats, 18s in all (DEX to 20 and 19 INT due to High Elf).

Level 1 has you sitting at a 10+5+4 Nekkid AC of 19. Throw in a +3 Shield, and you're at 24. I have a good reason for going Elf instead of where many do.

Next, go Wizard for 2 levels to get the Blade Dancer Arcane Tradition to add your INT Modifier too, as it isn't an "Unarmored Defense" equivalent. So you can get another +4 to that AC, but you lose the Shield at this point. Make sure one spell you do take is "Mage Armor" to increase your Base AC to a 13.

So for Level 3 (Barbarian 1 / Wizard 2) you'd have 13(Mage Armor)+5(Dex)+4(Con)+4(Int) = 26 AC with NO MAGIC ITEMS.

For the next 5 levels, we'd work on leveling those two classes to 4 so you get the Ability Score Increase. Improving Constitution or Intelligence each time since an ASI from this ability can't improve it beyond 20. This would raise it up two more points by 8th level to a 28 AC.

At this point, additional levels don't REALLY matter since you can't improve Base Scores through ASI, and since wearing armor is going to lose you 3 or more points from the AC score, you're not going to want to mess that up. And wearing a shield, will get you no net gain (+3 shield give +5 AC, which loses the Blade Singing bonus which is your INT modifier, also a +5 at this point).

From here on out, any and all improvements will be gained via Magic Items or through playing with RAW.

One way, as has been said, is to get the Ability Score improving books. As a High Elf, you're likely to "live well over 700 years" which, for sake of argument, we'll say you started adventuring as an elf at the child-like age of 50. We'll say you stole these books from the library of your starting city, not realizing what they were. The ones that would benefit you most as a Barbarian 4 / Wizard 16 (Since for some of this, I need access to 7th+ level spells) would be: Manual of Bodily Health (Constitution), Manual of Quickness of Action, and the Tome of Clear Thought. Assume you read each of these which increase the scores by 2. The first time reading these gets you a +3 to that already large AC, a 31. Then, let's attune our first magic item, Bracers of Defense, this raises it to a 33 since we're not wearing armor, or using a shield, throw in a Ring of Protection, and an Ioun Stone of Protection, and we're at a 35 (+1 AC from both). Next, we'll assume we use a full "Deck of Many Things" and get REALLY lucky with our draws and get the Star and boost our INT up and raise it to a 36. We'll also assume we get the Moon and max our "Wish" number (These come into play later) at 3.

Alright, as it stands we're at a whopping 36 AC. Let's progress the clock until you're 150 years old. You've just gained another +3 and you're now at 39. Lather, Rinse, Repeat. 250: 42 AC, 350: 45 AC, 450: 48 AC, 550: 51 AC, 650: 54 AC, 750: 57 AC. By this time, you're getting up in years, despite it saying "Well Over 700" we're unsure how old they actually intent to allow you to get. So we'll assume you won't make it to 850... naturally...

Now we're messing with the RAW. By this point you've probably got a well established family and are well on your way to becoming a legend. You know that you can tell your family to leave your three books alone, and they would.

So you go ahead, and use a spell slot and cast "Sequester" on yourself with the set rule to not be awakened for 100 years. You'll be left there, perfectly fine, unless someone finds and dispels the magic before the 100 years. You can use this method, basically indefinitely to raise it well beyond the 57 AC we're sitting at before that.

You could also use your ability from the "Wish" spells you technically gained through the Moon card to wish to be able to lower the age of your physical body to a point such as 50 (Where you started), but to retain all the improvements and mental advantages you had gained through your years of experience... Basically, this one works BEST if you are a lawyer and can actually prevent any and every loophole possible to keep your skills and scores where they were to get you that 57 AC as a 50 year old elf, and possibly start your career anew and start using the books again. Or use a new set that you could have made during your wait since you'd have had the, well over 6,000 days to make a new set (2,000 each since they're each 50,000 and divide that by 25 to make to determine the days required). From that point on, you could go through that process two more times without having to worry about needing to find a new way to get "Wish."

tl;dr End Tally is a 57 AC without hitting a ceiling for the age of a High Elf.

Answer 6

1 cleric 19 Wizard . Plate +3 armor +11 (can have resistance or immune to critical hits), Shield magic +3 =+5, Shield of faith spell +2, Shield spell +5, Ring of defense +1, Staff of Power +2 (or Defender weapon +3), Cloak of Displacement (basically a +2) all attacks are disadvantage Ion stone of protection +1: Total= 38 (40) attacks disadvantage

OR...1 Barbarian, 19 Wizard, Robe of Magi 15+ dex, 22 dex +6, 22 Con +6, Magic Shield +3 = +5, Shield of faith spell +2, Shield spell +5, Ring of defense +1, Staff of Power +2 (or Defender weapon +3), Mage Armor +3, Cloak of Displacement (basically a +2) all attacks are disadvantage, Ion stone of protection +1: TOTAL = 47 (49) attacks have disadvantage and no special circumstances

You could potentially duel wield two defender weapons (+3 each) and use bracers of defense so that the bonus is equal to a magic +3 shield...then take defense duelist for an additional +1ac.

Answer 7

The highest AC I've had for a character (without going so overboard as to be ridiculous) is AC31 the character is a goblin paladin wearing +3 mithril plate and a +3 shield with a Dex of 20...going overboard its possible to hit AC41 (Dex of 30, cloak of protection, ring of protection, Defender +3, +3 mithril plate, +3 shield...This assumes alot of exp past lv.20 to get Dex 30 (DMG states at lv.20 characters can go up to 30 but not higher than that using the attribute increases given for every 30k exp above 355,000exp)

Answer 8

We can reach a permanent AC of 36.

As a barbarian lvl 8, monk 1, dragon bloodline sorcerer 1, my ac would be 13+dex+con+wis.

By level 8, it is possible (albeit unlikely) to have 20 in 3 stats. We'll assume we've reached that point. That puts us at 28 AC.

We use the manuals for Wis, Con and Dex, which brings us to 31 AC.

Ring of protection +1 and cloak of protection +1 gives us 33 AC. Defensive Sword with all bonus to AC puts us at walking around with 36 AC.

Answer 9

Well you can actually get to 40.

First you need to be a werebear or a warforged; both grant +1 to AC. Then you need a level in Sorcerer with dragon origin base, making your base AC 13, and a level in Barbarian to add your Con and Dex to AC. Then you can get Wis and Dex to 24 using a Deck of Many Things and then use Manual of Bodily Health and Quickness that can give you another +2 to each Con and Dex making each 26. Then you need bracers of defense for a +2, a ring of protection, a cloak of protection, and ioun stone of protection — which all give a +1 — and finally a shield +3.

13+1+8+8+2+3+5=40

Now you still have 18 levels to play with and it is still possible to use a shield spell on yourself using Sorcerer.

Answer 10

Well, manuals allowed, you could use them an infinite number of times if you had a mirror of life trapping. Thus, you could have a nearly infinite AC.

Answer 11

Most games allow you to have equipped 2 magical items, 2 attunement slots and as many not attuning magical items as you want, most DM's allow you to carry a bag of holding as well. So you are stuck with a lot of physical weaknesses right off the bat.

The max bonus to AC on armor is +3, and no unarmored defenses don't stack. Reading a book won't necessarily work as most DM's don't even know what that is or how it functions.

Waiting out the period to increase your AC is pointless as then you would have to drop that character and watch the DM make him a god over time since you need to continue with the campaign.

The next biggest weakness is AOE spells, all you guys are talking about is increasing your AC, and yes this question is about what is the highest AC you can reach but that's the least conventional way to do things.

But sure, let's make a max AC character.

First off, shields don't require attunement and stack with everything, even spells as long as you have war caster. that's +10AC right off the bat.

Finding the highest base armor rating is difficult, however it's the barb 20, paladin 3 and fighter 1 that end up tying at a total of 21 AC. Cleric's can go there as well but why i said paladin 3 is because of the fighting style making the fighter the cheapest and most effective high AC at 22. That takes up your first equipped magical item with your armor, the second strongest is the defense sword, however that's a legendary and you are already wielding a shield with the same bonus as it so we will stick with the shield for math calculations to get the cheapest AC build possible.

Right now we sit at 32 AC base.

• Drinking a potion of speed adds +2 AC,
• Shield grants +5 AC for one turn only,
• Shield of faith adds an additional +2 and so does another cleric spell.
• Since we can only get a +3 AC gauntlet with our final attunement slot we will get just that.

35 AC standard with two shields. Stack Haste spell, Speed Potion, Shield spell, Shield of Faith and the final spell of which i am too lazy to look up the name of, you gain the final and MAX AC within a legit campaign at drumrolls 48 AC without situations.

Stack on 3/4 cover you reach 53 AC. Being prone against rangers is helpful since that's automatic 1/2 cover if they are on the same ground level or 3/4 if slightly below along with their disadvantage on attacks. However under no circumstance can this number be modified which is what the other people tried to fix with adding barbs and those filthy books.