What is the highest possible AC?

  • 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.

  • 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.

    Comments are not for extended discussion; this conversation has been moved to chat.

    Special note: bladesinger is mutually exclusive with shield, and at 20 int gives only the +5 that a +3 shield would give you, but it allows for the dual wielder feat (+1 ac) and (with the feat) dual wielding staves of power. (+2 each). The +1 from dual wielder takes the light armor profile to 27, and the extra staff of power gives you an extra +2 (as well as another stat to look for manuals in). It's not always on, exactly, but 2 fights per short rest is pretty good.

    Surely you can choose all three of Ring of Protection, Cloak of Protection, Ioun Stone - Protection at once

    No because Staff of Power requires attunement. More verbose: You can choose 3 of Staff of Power, Ring of Protection, Cloak of Protection, and Ioun Stone, but you will always choose Staff of Power as one of the slots because it gives +2 to AC, others give only +1.

    The warforged from wayfinder's guide to eberron can increase this by 1 from level 17 onwards, as they get an ac of 16 plus proficiency with the heavy configuration, and it allows shields as well. You could argue that it doesn't count as armour, but you could in theory wear armour as well just to make sure you get the benefit from Defense fighting style

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Content dated before 6/26/2020 9:53 AM