AC: How high should it be? [Archive] - Giant in the Playground Forums

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NecessaryWeevil

2016-09-22, 06:33 PM

Naanomi

2016-09-22, 06:41 PM

Depends on magic item availability; other methods of survivability you have; and if you tend to fight stock monsters or custom/class level foes.

At level , 15 AC is good. Higher than that, the absolute floor for a frontliner is probably 17 AC?

Kryx

2016-09-22, 06:44 PM

So our group has noticed, especially as one reaches higher levels, that attacks rarely miss because AC rarely gets higher than 20-22
Uh, this seems to be an issue with the enemies you're facing then. If you fight a collection of enemies that average out to your current level PCs have a 65% chance to hit across their whole career. 35% miss is pretty ideal from a game design perspective.

PCs top out at +11 to hit (not including magic items). That shouldn't be an automatic hit.

If you're playing with +X magic items then the system isn't built to handle them and I'd recommend not doing do.

To see a monsters to hit on average see DPR of Classes monster stats (https://docs.google.com/spreadsheets/d/1d-9xDdath8kX_v7Rpts9JFIJwIG3X0-dDUtfax14NT0/) under "monster to hit rolling average". From that you can calculate the chance that you'll be hit.

Ryuu Hayato

2016-09-22, 08:39 PM

On my table, the lvl 20 fighters don't have more than 21 AC. No +x weapon, shields and armor instead I give to them +1d6 weapons or 2d6 weapons. One cloak of protection or ring of protection.

Try in the max give them +2 on AC with magic items the require attunement, and for weapons give to them 1d6 elemental damage, like flame tongue or frost brand.

Slipperychicken

2016-09-22, 08:59 PM

tl;dr: Your AC should be as high as you can get it while still doing your job properly. Everybody needs to be able to take a hit. If you're supposed to be in melee, you cannot afford to be fragile.

The marginal returns, in terms of reducing the damage you take, do not change barring situations where you hit on a 2 or only get hit on a 20. In absolute terms, going from 16 to 17 is the same quantity as going from 12 to 13.

In terms of the percent of the damage you were taking before, it actually increases with increasing AC. If you turn an enemy's 25% hit chance (needs a 16 or higher to hit) into a 20% hit chance (needs a 17 or higher), then that cuts the expected damage you take by around 20% (25-20/25 = 20%). That means in that specific case, in terms of the number of attacks that can be made against your character, 1 extra point of AC would be similar to raising his hit points by 20%.

The point of "diminishing returns" only happens when you exceed your enemy's tohit bonus plus 20. Any AC over that point does not reduce hit chance because the enemy can always hit on a 20 anyway. That is so high that you will almost never hit it, barring theorycraft levels of AC pumping that are unlikely to happen in a real game.

Zman

2016-09-22, 09:09 PM

Low levels, AC 15-18. By Mid levels 17-20.

Magic items can bump this up, but shouldn't by more than +1 or +2 in most cases before bounded accuracy starts to crack.

Naanomi

2016-09-22, 09:28 PM

Safety Sword

2016-09-22, 11:37 PM

With the option to have magic weapons without +X boosts that should be the norm.

As others have stated, the system isn't built to stack to hit bonuses. Combat is pretty boring if you always hit I think... well.. too predictable in any case, you can still build good encounters where no one misses.

Specter

2016-09-23, 07:55 AM

Playing as a level 8 EK with 22AC (27 with Shield) I say AC is of the essence. I've been the last man standing in my party three times and that's all thanks to these numbers.

malachi

2016-09-23, 08:02 AM

Monsters in the MM go up to +18 to hit (I think that is the highest); and a few super monsters in modules beat that I think... so even in a high-magic game you will be unlikely to hit the point where more AC doesn't matter; but also there shouldn't be a point where well armored people should be hit 'every time' and give up on AC

If the enemy has +18 to hit, and your AC caps out at 21 (heavy armor + shield + defensive style), you're getting hit 90% of the time, almost the same as if you dropped your armor and shield and went up against that enemy in your naked AC 9. Even with +3 armor, you're getting hit 75% of the time - so 3 hits for every 1 miss. You'd need a +2 AC buff on top of that (Shield of Faith?) to get to the 65% range that Kryx suggested (assuming that hit chance for PCs should match hit chance for enemies).

Tanarii

2016-09-23, 08:10 AM

Uh, this seems to be an issue with the enemies you're facing then. If you fight a collection of enemies that average out to your current level PCs have a 65% chance to hit across their whole career. 35% miss is pretty ideal from a game design perspective.Besides answer the wrong question, this isn't necessarily true. As PCs level up, they have more opportunities to face large numbers of lower CR creatures instead of (approximately) equal CR creatures. For a couple of reasons: there are more lower CR creatures available for a DM to use, and the ability to actually use large numbers of (not-giant-rats) creatures at all starts to come online as they level up.

Of course that's campaign dependent and YMMV. But compared to a white-room extreme-CaS calculations based on small group of increasing and constantly (approximately) equal CR foes, it certainly pans out in actual play IMX. (Caveat: I rarely play or DM very high level 5e, so my experiences may be off at those levels.)

This of course has ramifications for player AC too. Those lower CR creatures get more attack rolls (since there are more of them now), but they still have the same hit bonus and do the same damage on hit. That means increasing HP is as effective or even a more effective defense, as intended by the bounded accuracy design philosophy. It also is why I tend to see players value more Con / HPs more than AC.

Naanomi

2016-09-23, 08:11 AM

Or... 90% to hit VS 95% to hit is half the chance of being hit by the Kraken compared to any of your peers. Hopefully (with bound accuracy keeping 'lesser' monsters viable) you aren't just fighting Kraken after Kraken

But yes, that is why any real 'tank' also needs ways to spike their AC, other ways to mitigate damage, and good HP; it just isn't possible for 'one defense to rule them all' and ignore the rest

Kryx

2016-09-23, 09:01 AM

Besides answer the wrong question
The part I quoted did not specify if PC attacks rarely miss or monster attacks rarely miss.

The point being is that unless the GM is purposefully using much higher CR monsters on a regular basis (which is unlikely as you pointed out), this is likely a perception issue, poor PC build issue, or GM purposefully increasing +to hit or fudging rolls.

Assuming your method is correct, that the enemies vary between many lower and a few higher, the chance to be hit would be even lower than I put above.

R.Shackleford

2016-09-23, 02:27 PM

AC is only as important as your DM makes it.

Some games you want as big as possible and other times you may as well forget about it.

I've been in games were the DM threw traps (Dex saves), spells (saves), and Athletics checks at the party like 90% of the time.

And this wasn't even the Fort/Ref/Will type of games my groups run, the DM was a new one that wanted to run an adventure they made.

Rerem115

2016-09-23, 02:46 PM

Playing as a level 8 EK with 22AC (27 with Shield) I say AC is of the essence. I've been the last man standing in my party three times and that's all thanks to these numbers.

Yeah, I've been in a campaign with an EK who pretty much got to decide if he got hit or not. He had full plate, a +1 shield, the Defensive Fighting Style, a cloak of protection, a ring of protection, and Shield.

Now, the magic items he had were supposed to be split up amongst the party, but when we saw just how much of a tank we could make this guy, we all pitched in to Voltron him up :smalltongue:.

He had a base AC of 25 (18+3+1+1+1), and could pump it up to 30 if something got past that. When we really needed a tank, he casted Blade Ward on his turn, and just dared enemies to get past him. With this guy, we were almost unstoppable; we had a tournament arc, and it took 3 Balors to bring us down. We still got one of them, and we were level 7 :smallbiggrin:.

ShneekeyTheLost

2016-09-23, 02:51 PM

I'm wondering if AC should be focused. I tend to find that AC matters less and less as you go into the mid to late game stage, so at that point, a tank should have some sort of damage resistance on call. Barbarians can get this easily enough, Fighters and Paladins have to jump through a couple of hoops to get their bases covered properly. Literally 'tanking' damage. Sure, I got hit, I just thought it tickled a little bit.

Combining DR with Resistance to Damage is probably going to be a surer thing than AC, or so it seems to me.

R.Shackleford

2016-09-23, 03:51 PM

Firechanter

2016-09-23, 07:54 PM

beargryllz

2016-09-24, 01:55 PM

20 is attainable somewhat early if you can find platemail and it's plenty fine for most of the game. Going higher means getting magical treasure or tweaking a typical character build to get higher AC bonuses

A really dedicated tank that sacrifices damage can get higher, but at some point you really have to ask if it's worth it. Really dangerous monsters are going to hit anyway, and trivial monsters won't even bother engaging in combat if you're seriously that untouchable.

I think most builds are better off getting right around 20 and then focusing on offensive stats or other ways to be defensive. I took heavy armor master and that has prevented a ton of damage over the life of my character, for example. I'll absolutely throw on a magic set of armor and get it higher, but my build probably won't really change to incorporate more AC

Specter

2016-09-24, 02:07 PM

20 is attainable somewhat early if you can find platemail and it's plenty fine for most of the game. Going higher means getting magical treasure or tweaking a typical character build to get higher AC bonuses

If a paladin gets the Defense Fighting Style, he can reach 23AC easily with Shield of Faith. Similarly, EKs with Shield can reach 26.

beargryllz

2016-09-24, 02:10 PM

If a paladin gets the Defense Fighting Style, he can reach 23AC easily with Shield of Faith. Similarly, EKs with Shield can reach 26.

I'd so much rather get dueling and be concentrating on bless though. I also like using my reaction for damage instead of mitigation most of the time, but that's a way different build

Cl0001

2016-09-24, 10:40 PM

Player AC can get really high depending on magic items and stats. Personally, the highest AC I've ever achieved was over 30. That was with my lvl 20 barbarian with a 22 unarmored AC, 5 AC from a +3 shield, +1 cloak of protection, +3 defender longsword and +2 for shield of faith. So AC can get really high and it's not extremely hard to get it that high. If there is low quantities of magic items though, max AC goes down quite a bit from weaker armor and shields. But, by 4th level, you primary tank should have an AC of at least 18, and everyone else's AC should be around 14.
Everything included though, don't worry about AC too much. If you can't get it above 20 at higher levels, don't bother. And if you're looking to be really tanky, go for resistances and Dex saving throws. Because at higher levels, they help out a ton more than a couple more AC

Kane0

2016-09-24, 11:53 PM

10 + (double prof bonus) is 'OK' AC, +2-4 for 'good' AC depending on level and access to magic items that boost it.
Higher AC is more valuable at lower levels than it is at higher ones since you have fewer HP and that is what largely determines your longevity in a fight. 5e is balanced on HP scaling as you level up more than attack/defense numbers, but the average attack bonus of enemies and the average amount of attacks against you also factors in.

Firechanter

2016-09-25, 07:59 AM

Back to the question about Diminishing Returns: even high-CR Monsters rarely have an Attack bonus >+10. AFB now so I can't check. But basically that point is reached when the opponents you normally fight can't hit you on a natural 19. Since a Nat20 always Hits, anything beyond that is wasted.

However, anything up _to_ that point yields not diminishing but increasing returns:
- if you're currently hit on a 17+, an increase by +1AC will save you 25% of damage.
- compared to being hit on 18+, a +1 AC will save you 33% of damage.
- and from a required 19 to 20 is a whopping 50% difference.
(Not factoring in extra damage from Crits)

MrStabby

2016-09-25, 08:25 AM

Besides answer the wrong question, this isn't necessarily true. As PCs level up, they have more opportunities to face large numbers of lower CR creatures instead of (approximately) equal CR creatures. For a couple of reasons: there are more lower CR creatures available for a DM to use, and the ability to actually use large numbers of (not-giant-rats) creatures at all starts to come online as they level up.

Of course that's campaign dependent and YMMV. But compared to a white-room extreme-CaS calculations based on small group of increasing and constantly (approximately) equal CR foes, it certainly pans out in actual play IMX. (Caveat: I rarely play or DM very high level 5e, so my experiences may be off at those levels.)

I think this pretty close to summing up the problem. If a DM is on the restricted mentality of looking at party level then looking across for a creature for a level appropriate encounter with one enemy then you will find that all the encounters are on one end of the scale of AC usefulness, i.e. the lower end. As you replace one high level enemy with more lower level ones the usefulness of AC increases. The number of extra rounds of combat bought by 1 point of AC is much more the higher they need to roll to hit in the first place.

If you face 3 CR3 enemies then it is likely that AC is more important than if you face one CR 10 enemy. If you face 15 CR 1/4 enemies then it will be even more important still.

Kryx

2016-09-25, 08:26 AM

If a DM is on the restricted mentality of looking at party level then looking across for a creature for a level appropriate encounter with one enemy then you will find that all the encounters are on one end of the scale of AC usefulness, i.e. the lower end.
Can you please provide math to prove this claim?

MrStabby

2016-09-25, 08:43 AM

Can you please provide math to prove this claim?

Sure it's not hard.

Ok say you get hit with a roll of X vs the high CR creature. An extra point of AC means you get hit hit on a roll of Y=X+1. So probabilities of being hit is 21-X and 21-(X+1) respectively.

The relative frequency of being hit is one divided by the other: (21-(X+1))/(21-x)=(20-x)/(21-x)

You will immediately notice that the higher X is the bigger this ratio is: if X is 19 then it means you are being hit half as often for one additional point of armour. On the other hand if x=11 then you are being hit 9/10ths of the time due to one additional point in AC.

The time you survive is inversely proportional to the rate at which you are hit. If you are hit twice as often you have half the number of turns to do damage as you otherwise would.

Kryx

2016-09-25, 08:50 AM

MrStabby

2016-09-25, 09:08 AM

Please summarize your claim. Are you saying that the more enemies you face the more important AC is? That doesn't quite compute.

10 chances to hit you at 55% chance to hit for 4 damage vs 1 chance to hit you at 55% for 40 damage average to the same and AC has the same value on average.

No. I am saying that the lower the probability of hitting an enemy has, the bigger impact that an extra point of AC has.

For a given level of encounter difficulty, the more enemies there are the lower CR those enemies will be.

The lower the CR of an enemy, the higher number they will tend to need to hit a given AC (in general ).

djreynolds

2016-09-25, 09:15 AM

So our group has noticed, especially as one reaches higher levels, that attacks rarely miss because AC rarely gets higher than 20-22.

Where is the point of diminishing returns, in your opinion? What is "good enough" AC at levels 5, 10, 15 for a melee fighter?

If I asked specifically for my Rogue/Fighter/Barbarian who will be built mostly for damage output but share tanking with a Battlemaster fighter, would your advice change?

It's not just AC. It's a combo of damage output, and damage taken. Theses classes are each unique. A barbarian can not rage all day, uncanny dodge is once a turn on one attack. EK shield spell is limited.

The Dodge action is viable when you have to stay put. Sometimes you may go with or without a shield.

If you are a frontline warrior. You need AC, HP or a means of damage reduction, and team work. Can you hold long enough for your team mates to aid you?

A standard fighter, can have an AC of 21 with plate and shield and defensive style selected. And put out good modest damage, consistently. Good HP, con saves, resilient something, and a combat feat.

If you are playing this and getting whipped, disengage and retreat.

I find an AC of 18 is acceptable. Chain and shield will carry you along time. If not, then max out con and save your gold for plate. Be nice to the cleric and make the wizard look good and let the rogue steal a few coins now and again.

And remember you are the predator.

Spore

2016-09-25, 09:42 AM

One time I read something to the effect of "if you can't get your AC to 21+, you needn't bother at all."

Seeing how our last campaign went, I am inclined to agree.

We had a Bladesinger in the party who was basically unhittable, while everyone else floated around AC 16-18. I had 18 and got hit all. the. friggin. time. And when I buffed up to 20 I _still_ got hit all the time! But, when I scored some better gear and reached AC 21 (before buffs), it immediately got _much_ better.
So, yeah... meaningful AC starts at 21.

It is really just a percentage based thing. +2 AC is 10% less likely to be hit. Halfing the enemies hit chance from 20% to 10% is significant. Getting down from 80% chance of being hit to 70% is not as impactful. That is why focussing AC can be a big part of tanking damage.

Our barbarian is intuitively concerned about her AC of 16. Now that is a good AC for 3rd level but of course it won't cut it going on. AC starts to scale but at a much lower rate than in 3.5 People expect to stay tanky just from class features but what they forget is that spells are class features as well and most mundane classes just get utility (and damage) from their features, not tanking ability (aside from the Paladin). You get no new armor proficiency. You don't get bonus AC and only the occasional disadvantage on enemy attack rolls.

We will have to invest into her and the Paladin's ability to mitigate damage. We will most likely just go the other way into alphastriking the most potent enemies with our group setup (ranger, rogue, oath of vengeance and barbarian) in order to inflict the worst status conditions onto them: dead.

MrStabby

2016-09-25, 10:05 AM

It is really just a percentage based thing. +2 AC is 10% less likely to be hit. Halfing the enemies hit chance from 20% to 10% is significant. Getting down from 80% chance of being hit to 70% is not as impactful. That is why focussing AC can be a big part of tanking damage.

Our barbarian is intuitively concerned about her AC of 16. Now that is a good AC for 3rd level but of course it won't cut it going on. AC starts to scale but at a much lower rate than in 3.5 People expect to stay tanky just from class features but what they forget is that spells are class features as well and most mundane classes just get utility (and damage) from their features, not tanking ability (aside from the Paladin). You get no new armor proficiency. You don't get bonus AC and only the occasional disadvantage on enemy attack rolls.

We will have to invest into her and the Paladin's ability to mitigate damage. We will most likely just go the other way into alphastriking the most potent enemies with our group setup (ranger, rogue, oath of vengeance and barbarian) in order to inflict the worst status conditions onto them: dead.

There is also the aspect that you can tank by imposing disadvantage on attack rolls. Spells and abilities that do that can be effective. Not a big point but a small supplement.

Iron Angel

2016-09-25, 10:23 AM

Resistance to damage types is the best defensive stat. It halves damage received. Whats not to love? Its why Barbarians are so tanky, the majority of the damage you receive in this game is going to be piercing, bludgeoning, or slashing, and resisting those forms of damage extends your lifespan considerably.

djreynolds

2016-09-26, 06:11 AM

There is also the aspect that you can tank by imposing disadvantage on attack rolls. Spells and abilities that do that can be effective. Not a big point but a small supplement.

Resistance to damage types is the best defensive stat. It halves damage received. Whats not to love? Its why Barbarians are so tanky, the majority of the damage you receive in this game is going to be piercing, bludgeoning, or slashing, and resisting those forms of damage extends your lifespan considerably.

Its not just AC, good saves, damage resistance, high HP, healing, using appropriate tactics... like dodge or retreating... keeping it ranged if you can. Using stealth to avoid stuff in the first place.

I like it.

Willie the Duck

2016-09-26, 07:53 AM

Its not just AC, good saves, damage resistance, high HP, healing, using appropriate tactics... like dodge or retreating... keeping it ranged if you can. Using stealth to avoid stuff in the first place.

I like it.

Perhaps, but the OP question was what is an appropriate AC for level ___.

Asmotherion

2016-09-26, 09:05 AM

If you are a barbarian, your AC should have no trouble getting around 23-24, or 28-31 with magic items (Remember that Unarmored defence applies when using a shield, and you can get a +3 shield by level 20, Bracers of Defence, Ring of Protection). If you can get your hands on a tome of dexterity and one of constitution, you can make this a net 32-33.

Let's assume you get it around 32. The norm for a character (and thus, I'll count this as the average) at level 20 is +11 to attack rolls (With no magic items, which is for a normal, non boss encounter). That means that, even with a critical hit (natural 20) the score is 31, still lower than you AC (well, it WILL hit you, I just want to prove a point here).

So, to find your answear, calculate an average attack bonus at your level, and add 20 (which is the maximum attack one may get from a die roll). The higher one needs to roll at your respective level to land a hit on you, themore awesome your AC. You can also compare this to monsters from the Monster Manual (and their respective attack bonus) to see how much they have to roll to hit you.

A low AC is an AC that, at the current CR you are facing, the attack bonus of monsters and things you are facing is enough to hit you with let's say a 5-6 on the d20 (Or less than 25% protection/miss chance). With an averace AC, monsters of your CR would hit you with a 10-11 roll on the d20 (Which is 50% protection/miss chance). An AC that makes you protected from rolls of 15+ is a good AC (75% Protection/miss chance). If everything at the current CR you're facing needs to roll a natural 20 to hit you (thus 99% protection/miss chance), you are an awesome tank.

I hope this answears your question.

Now, the maximum AC I've been able to build is with a Sorcerer 1/Barbarian 1/ Wizard 18. Never actually played the character, just theorycrafting. It's a very MAD character but get to hit a static AC 28 without items (provided he uses every one of his reactions to cast Shield, which he can cast At-Will) or 30 with just a regular, non magical shield. With magic items, this goes up to 38 (He is wearing Robes of the Archmagi, uses a staff of power and wearing a ring of protection as attuned items. He also has a +3 shield, that does not require attunement). This is the best build for persistant AC I've found. Make the Wizard an Abjurer, and he'll never fall. Or if you want an equally strong attack, get him hex with Magic initiate, and give his a level 2 magic missile as a second at-will spell. Or maybe get him Armor of Agathys for more temp HP.

About saves, you can always counterspell enemy casters, at the cost of 5 AC. Dex saves, you should have no problem passing those, nor Con saves (As you are going to maximise your Dex and Con to 20 asap). If something requires an other save, you should be able to counter-spell it. If it is magic missile, you have Shield at-will as we said earlyer. Your Intelligence is going to need to go up, if you want to effectivelly counterspell things of higher spell slots. Also, at the begining of battle, you can cast Globe of Invulnerability on yourself, using an 8th or 9th spell slot, to save yourself from too much counterspelling. Dispell Magic should be there just in case you're facing more than one enemy spellcaster. You should eventually be able to down everything by slowly cutting HP with your Hexed Magic Missiles wile taking 0 to minimal dammage.

For example, the Terrasque has a +19 to hit. That means that the terrasque should roll at least 19 on a d20 to hit this Wizard. The next highest attack bonus is the Ancient Red and Gold dragons, who have +17 to hit, meaning they must roll a natural 20 to hit you (they still don't match your AC, but a natural 20 means an Auto-hit and an auto critical). Everything else is even lower. However, be carefull about pissing off your DM, and don't brag too much about it, or the DM might make it his personal mission to kill you. And, however strong you might be, the dm can always give you a heart attack or make a giant meteor fall on your head (not a spell, an actual meteor), and remind you why you should not brag about being unkillable, wile he was so kind and allowed you to pull this build, trusting that you would not abuse the power bestowed uppon you.

djreynolds

2016-09-27, 03:33 AM

All good till a beholder shows up with his anti-magic eye stalk.

Magic is tough to determine. If you get it or not.

I would try to base it around a standard fighter, a champion at say level 10 could have defensive style, plate as he can now afford it easily, a shield... AC21. An EK could have 26 once a turn, if selected defensive style

So around level 10 your standard fighter should have 20-21, and an EK could have AC25-26. All non magical. This is a good place to look at. and paladin and cleric could have 22 with shield of faith

At level 5, you might still have chainmail and shield 18, and paladin and cleric could have 22 with shield of faith

At level 1, chainmail and shield 18. obviously a paladin and cleric are in there

But like CoS, I got +1 AC for something, so my cleric had an AC19 or AC23 with shield of faith.

Willie the Duck

2016-09-27, 09:20 AM

Since we can all agree on studded leather plus dex 20/breastplate and dex 14/ or platemail and dex 10 (plus shield unless you think the higher damage output is needed), perhaps the better question would be what add-ons one should expect at level X in order to stay competitive.