# Average/optimal AC for core classes per level

I've seen time and again that someone mentions someone has a low or a high AC for his class. So I'm wondering: Is there something like a list for what AC the core classes should have per level (averagewise or optimalwise)?

So the challenge with this question is that it's not just about classes but also about resources expended. You could be a Fighter choosing to use leather armor and two daggers or you could be a shield and heavy armor Fighter with the same stats and have a very different AC.

The other complication here is Touch AC vs. Flat-footed AC. Most characters are good at one or the other but not both.

That stated, there are really only a couple of builds that really matter here for benchmarks, so let's run some comparisons. Note that it's really less about "class" and more about "feats" + money.

The Tank: Heavy Armor + Shield

I modeled this one as a Fighter spending ~75% of their cash on defense.

• Level 3: 24 (Full Plate +1, Heavy Shield, Dex +1, Dodge +1)
• Level 5: 28 (Heavy Shield +1, Ring of Protection +1, Amulet of Natural Armor +1)
• Level 7: 31 (Full Plate +2, Heavy Shield +2, RoP +2, Dex +2)
• Level 9: 36 (Full Plate +3, Heavy Shield +3, AoNA +2, Dex +3, Dusty Rose Ioun Stone +1)
• Level 11: 40 (Dex Belt => Dex +4, Armor/Shield +4, Ring/Amulet +3)

The Light Armor Dex build

As above this Rogue is spending most of their money boosting their AC. In this case, they benefit greatly from the Dex Belt as well.

• Level 3: 20 (Mithril Chain Shirt +1, Dex +4, Dodge +1)
• Level 5: 23 (Dex +5, AoNA +1, RoP+1)
• Level 7: 25 (Chain Shirt +2, AoNA +2)
• Level 9: 28 (Chain Shirt +3, Dex +6, RoP +2)

The Wizard/Sorcerer (with some Dex)

As above, this person is spending lots of their money on basic defensive gear and using the Dex to benefit their ranged touch attacks.

• Level 3: 15 (Dex +3, Bracers of Armor +1, RoP +1)
• Level 5: 18 (Dex +3, Bracers +2, AoNA +1, Draconic Natural Armor +1)
• Level 7: 21 (Dex +4, Bracers +3, AoNA +2)
• Level 9: 25 (Dex +4, Bracers +4, RoP +2, Draconic Natural Armor +2, Dusty Rose Ioun Stone +1)

Some Takeaways

These are "max" numbers not median numbers by any stretch. In fact the numbers should reveal several things:

• Dex is really important for AC outside of Heavy Armor characters, this constitutes most of your AC.
• By level 9 the spread on AC is huge. This actually causes big problems If your fighter has AC 30 and your Sorcerer has AC 18 (typical) then you end up with creatures that can never miss the Sorcerer if they can also hit the Fighter.
• This problem only gets worse as levels go on. At some point, you stop attacking fighters and just start casting spells at them because your odds of success are better.
• Likewise creatures become impossible to "balance". Take a CR20 Red Dragon, Wyrm, it has a bite of +38. Your Sorcerer is never going to have an AC to counter that. It basically means that the Sorcerer cannot get into melee combat or it will be ripped to shreds. It doesn't matter if the Sorcerer has dropped 500k on AC items or 50k on AC items.
• Some math (Bracers +8 => 64k, AoNA +5 => 50k, RoP +5 => 50k, Belt of Dex +6 => 36k). That's 200k in AC pump for a net AC of 31. Add a Shield spell and you're still under the threshold. You'll need Morale or Luck bonuses from a Bard or Cleric bring that up to 40+ and even then, you'll probably get hit.

There are 4 defenses

• AC is not the only defense. In fact, as levels go up your Ref/Fort/Will saves become far more important. No amount of AC will save you from a Wail of the Banshee.
• Experienced players understand this problem. At some point it becomes pointless to try to max out AC and instead you throw the resources into other things. Cloak of Resistance is far more important than Ring of Protection. At some point, instead of another +1 to your armor, you buy Energy Resistance or something to give you Damage Resistance.
• There are other ways to avoid getting hit. Mirror Image, Invisibility and Fly are all important abilities that allow weaker AC creatures to survive combat.
• AC is really only one part of the puzzle. For many combats, keeping certain characters protected is just as important.
• Level 3: 17 (Dex +3, Bracers of Armor +1, RoP +1) for sorcerers: where do the reamining +2 come from? also does armour/shield (spells each) help somewhat there?) – Thomas E. Sep 13 '14 at 10:18
• I did this over lunch. .. it's quite possible my math is wrong double checking now. – Gates VP Sep 13 '14 at 14:32
• So I fixed the Sorcerer number they were high by one or two points. – Gates VP Sep 13 '14 at 14:36
• Don't wizards/sorcs typically use magical mithril bucklers to get a bump to their AC? Also, no one will spend cash on bracers+4 when you can just cast mage armor. – starwed Sep 13 '14 at 17:07
• @starwed So the Mithril Buckler is actually a good cheat, that sidesteps all of the proficiency rules and the arcane spell failure rules. That stated it costs 2k for a +2, so it is expensive, for the same relative gold cost, it is adding a +1 to AC, possibly +2. It's also subject to some DM decisions around requirements for Somatic casting. General rules seem to be that you need one hand available for the somatic component and the buckler is clear that you lose its bonus when you use that hand. So if you use a Rod to cast, you lose the AC bonus. – Gates VP Sep 14 '14 at 7:35

The vast range of options for different classes means that a "Base AC" is going to be highly variable depending on what the character has picked or is aiming to achieve.

However the pazio reference NPC Codex contains sample core classes that we can use for this data; from that we get for example:

Monk
Level  AC
1      16
5      17
10     21
15     28
20     34


However this data is specialised through each level to different subtypes, but it gives you an idea of the scope of the issue.

• ^^then I really wasn't far off when I thought that an AC of 26 is way more than a lvl 10 would have and more in league with what a lvl 15 would have (was a gut feeling back then during my discussion with my player) – Thomas E. Sep 12 '14 at 9:41
• Good point there with the monks btw forgot about them as they are a good example as their base AC isn't equipment based. Do you know btw what an appropriate bonus to AC through magic items is at those levels? (or is that included/taken into account in that chart?) – Thomas E. Sep 12 '14 at 9:42
• Equipment is included with each of the example classes. – Rob Sep 12 '14 at 9:54
• Bare in mind also that players optimising for AC can easily exceed these values; they're examples rather than "ISO standards" – Rob Sep 12 '14 at 10:26

Sadly, there's no ISO benchmarks for AC on a per-class/level basis. BUT, you can get a sense on your own.

Low: a build that does NOT use many discretionary resources (gold, feats, stats) for AC purposes.

Hight: a build that uses ALL discretionary resources for AC.

E.g. A level-1 fighter using core rulebook stuff:

LOW: Scale-mail, Dex of 10, no AC feats, no shield: AC of 15

HIGH: Breast-plate, Dex of 14, Dodge feat, heavy shield: AC of 21

There's obviously more that one can do, but a 21 AC is solid for a starting tank.

• I thought I would never had to hear about ISO benchmarks after my graduation paper. I was wrong. – Zachiel Sep 11 '14 at 15:37
• THen we should talk with the ISO commitee :) What I'm wondering is about lvl 5 or 10 (had a player comment that his ranger would have a good AC until lvl 10 with an AC of 26 (10 coming from armour, 6 from dex), while I thought that is more lvl 15 there with that AC. – Thomas E. Sep 12 '14 at 5:38

The rule of thumb we go by is your level + 20 for ac. (This does not apply at early levels, although if you have 18 ac at level 1, that is good (At level 1 opponents average +1 or +2 to hit, they would need a ~16+ on die to hit you with 18 ac). The reasoning is because your opponents attack bonus will consist mostly of their BAB and the 20 sided die roll. Your level + 20 is saying that your opponents chance to hit is based off their weapon bonuses + relevant ability modifier * 5%. So if your opponent has 18 str, a +2 weapon, and a +1 bonus from feats they will have a 35% chance to hit you (4 str + 2 weapon + 1 feat = 7 * 5 = 35%).

The class you are playing, however, does not matter. If you break a class down by what separates them from all the other classes, the major differences are:

1) Base attack bonus
2) Fort, Refl, Will Saves
3) Hit Dice
4) Special abilities

You choose how you place your ability scores and rarely does a special ability from a class add into your AC (Monks with Wisdom would be an exception, but the wisdom would replace the armor bonus temporarily). The point is, your opponents attack bonus does not change depending on the class YOU are playing. Anyone can take a cleric, or a rogue, or a fighter, and give them the exact same armor proficiency feats, armor, and dex scores.

• The usefulness of a high AC does change, and while you can take a wizard and put him in full heavy armor, he'd be rather useless... Where is the 20+1 guideline from again? – Julix Sep 13 '15 at 2:47