I always get this for my sorcerers because I don't have any armour proficiency.(and I sometimes have bad dex stat)

So, if my Warlock’s unarmored AC is 14 (10+4Dex), does mage armor make my AC 17?

I never understood why this used dex and not int/wis

16

spell does what it says it does

13 + 3 dex mod 

:)

For those asking why the AC calculation is 13 + Dex modifier rather than 13 + Spell Casting Ability Modifier, I believe logic is as follows:

You're casting a spell that has the same effect of donning armor that has an AC of 13 which is also weightless and thus classified as "light" armor, thus allowing the addition of the full Dex modifier to the AC.

You could also look at it as though it works like a non existent item in the PHB equipment table under the Light Armor section right below Studded Leather called "Mage Armor" with the Armor Class of "13 + Dex Modifier"

I like to visualize this spell as a force field that is only a millimeter in thickness and so close to your skin that it might as well be touching it. I suppose you could even describe it as a magical body condom.

I also believe this is the logic for why it only works on creatures not wearing armor. It acts like armor and creatures usually cannot wear 2 sets of armor.

Why isn't this spell castable as a Ritual? 

the placement of the + tells you if it stacks or not like (Shield +2) is stackable, & Armour set the base for DC (Studded leather 12 + Dex modifier), this is why the placement of the + is importance for Stackable or DC Base.

I

is there any reason why you can't upcast mage armor?  AC 13 for level 1, AC14 for level 2 etc?

In that 2016 Sage Advice article, someone asks about the Bladesingers AC stacking, and the article states that we should not confuse Bonuses to AC, such as a +2, with an AC Calculation, such as 10+dex for unarmored AC. AC calculations DO NOT stack, but BONUSES to AC do in fact stack, such as a shield

If your DM is like that, he's no fun

Has anyone played with homebrews of this where at higher levels

a) apply your casting attribute (Int, or Cha) instead of Dex, i.e., AC becomes 13 + (Int or Cha), e.g., when cast with a level 3 spell slot

b) A/C base AC increases above 13, e.g., cast using a level 4 spell slot your AC becomes 14 +Dex, cast with a level 7 spell slot your AC becomes 15 +Dex?

Just wondering if/how unbalancing the idea would be?

does mage amor stack with the dragonborn feat dragon hide its for my dragonborn  star  druid ?

Quote from Neo_Nova >>

does mage amor stack with the dragonborn feat dragon hide its for my dragonborn  star  druid ?

No, it does not. Dragon Hide and this spell each offer an alternative way to calculate your base AC (though as it happens, they're the same formula). They don't provide a bonus to AC.

It's an abjuration spell so it's sort of a light force-field. The 3 AC would be the attack glancing off the forcefield.

Also I hate to burst your bubble but mage armor cannot be cast on top of monk's dexwis AC :(

Your monk/sorc CAN however cast Shield as a reaction which *will* stack on monk dexwis AC, however, thus being a 21 AC every time you cast shield

Here's a question no one has asked about Mage armor. With the wording, why would you think it can be cast on yourself? Willing creature? The word target is mentioned twice. Of course you would be a "willing creature", but the words are weird. Why wouldn't they throw in "or yourself" in the description? And it's a touch spell, you really need to touch yourself to cast it? The thing that really makes my point. A protective magical force surrounds "it". I think it was meant for others. Or there are very stupid people writing these feats and spells. Just saying... It's weird.

Quote from FoxMulder >>

Here's a question no one has asked about Mage armor. With the wording, why would you think it can be cast on yourself? Willing creature? The word target is mentioned twice. Of course you would be a "willing creature", but the words are weird. Why wouldn't they throw in "or yourself" in the description? And it's a touch spell, you really need to touch yourself to cast it? The thing that really makes my point. A protective magical force surrounds "it". I think it was meant for others. Or there are very stupid people writing these feats and spells. Just saying... It's weird.

"Why would you think it can be cast on yourself?"

Because it says "you touch a willing creature", and you are a willing creature that you can touch. Explicitly saying "or yourself" would be redundant, and, for better or worse, WOTC generally tries to avoid redundancy in things like this.

Generally any spell that targets a creature can be cast on oneself unless it specifically says otherwise. For example, the spell Thunderclap says "each creature within range, other than you..." There is no restriction like that in this spell, so you can cast it on yourself.

Possibly these words would be "weird" in normal conversation, but this sort of language is used very commonly in D&D spell descriptions. Saying that people must be "very stupid" for writing this way is needlessly cruel.

Cool!

Me and my friends play that with this and the 'dragon hide' feat, 2 things that both give +3 without saying they flat out give +3 do stack as long as every requirement is met, Ive ended up with some insane AC's that way but you do you!