Mage Armor is a 1st-level abjuration spell for sorcerers and wizards. You touch a willing creature that is not wearing armor, and its base AC becomes 13 + its Dexterity modifier for 8 hours. It needs no concentration. It ends early if the target puts on armor. For most wizards it is a +3 AC upgrade for one slot per day.
Mage Armor is a 1st-level abjuration spell that replaces a creature's normal unarmored AC with 13 + its Dexterity modifier. Sorcerers and wizards can cast it from 1st level. Since neither class has armor training, it is the standard way for them to raise their AC.
The value is simple. Unarmored AC is 10 + Dexterity, so Mage Armor adds 3. It lasts 8 hours without concentration, so one cast in the morning covers most adventuring days, and you can still concentrate on other spells.
It does not stack with other ways to calculate base AC. A monk, barbarian, or draconic sorcerer has to choose one formula. It also ends the moment the target dons armor.
| Property | Value |
|---|---|
| Level | 1 |
| School | Abjuration |
| Casting Time | 1 action |
| Range | Touch |
| Components | V, S, M |
| Material | A piece of cured leather. |
| Duration | 8 hours |
| Concentration | No |
| Ritual | No |
| Save/Attack | None |
| Classes | Sorcerer, Wizard |
| Metric | Assessment |
|---|---|
| Slot Efficiency | Excellent. One 1st-level slot for +3 AC over 8 hours. |
| Action Economy | Cast it before the adventuring day so it costs no action in combat. |
| Opportunity Cost | One fewer slot for Shield or Magic Missile. At low levels, that is a quarter or half of your slots. |
When worth the slot: Almost every day for wizards and sorcerers without another AC source.
When NOT worth the slot: When you have a better AC formula, or a short day where you will not be attacked.
Why it works: Eight hours covers most of a day. Cast it after a long rest, then again only if you rest and travel longer than that.
This avoids the mistake of: Spending your first combat action on it while enemies act.
Why it works: With Mage Armor, every +1 Dexterity modifier is +1 AC, plus initiative and Dexterity saves.
This avoids the mistake of: A wizard with 10 Dexterity who gets only AC 13 from the spell.
Why it works: The spell targets any willing creature not wearing armor. A familiar, a rescued prisoner, or an unarmored ally can benefit.
This avoids the mistake of: Thinking it is a self-only spell.
Why it's bad: Both set a base AC formula. You use one of them, not both. A monk with 16 Dexterity and 16 Wisdom has AC 16 from Unarmored Defense and 16 from Mage Armor, so the spell adds nothing.
Do this instead: Compare the two numbers and use the higher one.
Why it's bad: Mage Armor sets your base AC. Separate bonuses such as the Shield spell, Shield of Faith, or a Ring of Protection still add to it.
Do this instead: Calculate base AC first, then add each bonus.
Why it's bad: The spell ends if the target dons armor, and many casters lack armor training anyway.
Do this instead: Pick one approach: armor with training, or Mage Armor.
The 2024 Mage Armor keeps the same core: touch a willing creature not wearing armor, base AC becomes 13 + Dexterity modifier, 8 hours, no concentration. It is still on the Sorcerer and Wizard lists. The line about dismissing it as an action is gone. The spell now just ends early if the target dons armor.
The 2024 rules now state the one-formula rule plainly: a creature can only use one base AC calculation. A few class features changed around it. The 2024 Draconic Resilience gives 10 + Dexterity + Charisma while not wearing armor, so a draconic sorcerer with +4 Charisma beats Mage Armor. The Armor of Shadows invocation still lets a warlock cast Mage Armor on themselves without a slot.
Your base AC becomes 13 plus your Dexterity modifier. With 14 Dexterity, that is AC 15. With 16 Dexterity, it is AC 16. Bonuses such as the Shield spell are added on top.
No. Both are base AC formulas, and a creature can only use one. Use whichever gives the higher number.
No. It lasts 8 hours without concentration, so you can cast it in the morning and still concentrate on other spells all day.
Yes. It targets a willing creature you touch, as long as it is not wearing armor. Familiars and unarmored allies are common targets.
The spell only says the target cannot be wearing armor. Whether a carried shield breaks it is a DM call. Many tables allow it, but most wizards and sorcerers lack shield training anyway.
For an unarmored sorcerer or wizard, usually yes. It is +3 AC for 8 hours from one 1st-level slot. It is not worth it if you already have a better base AC formula.
Yes. Mage Armor sets your base AC, and Shield adds +5 to it as a reaction. A caster at AC 15 jumps to AC 20 until the start of their next turn.
It is not on the warlock spell list, but the Armor of Shadows invocation lets a warlock cast it on themselves at will without a spell slot. That is true in both the 2014 and 2024 rules.
Citations: SRD 5.1 (Mage Armor, Draconic Resilience, Armor of Shadows, Armor table); SRD 5.2.1 (Mage Armor, Only One Base AC, Draconic Resilience, Armor of Shadows)
Includes SRD 5.1 and SRD 5.2.1 content per CC BY 4.0.
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