D&D 5E Integrating Armor into the Proficiency System

Light Armor: Dex Bonus + Proficiency Bonus

Medium Armor: Con Bonus + Proficiency Bonus

Heavy Armor: Str Bonus + Proficiency Bonus

Mage Armor: Caster Stat Bonus + Proficiency Bonus

Just throwing the idea out there, to be ravaged by the forum wolves. :)

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First Post
Mage Armor: Caster Stat Bonus + Proficiency Bonus
I'd change it to bare proficiency bonus, otherwise casters will end with best armor bonus in the game.
Other than that I like that proposal quite a bit, should be interesting to see in play.

One thing though, armors themselves need to do something, and be different from eachother in the same weight category. DR seems like an obvious choice, but many people are against it, so what should it be?


I'd be perfectly content with armors just having categories like Light, Medium, Heave, and all armors in each category being identical rules-wise. Makes world-building a lot easier.


Well spellcasting DC's start at 8 now so why not AC.

No armor 8 + Dex mod
Light armor 9+ Dex mod + prof
Medium armor 10+ Con mod or Dex mod + prof -5 spd
Heavy armor 11+ Con mod + prof -5 spd and a penalty to stealth/jump/swim

Shield gives +2 AC

You end up with a Starting high AC of 11+3+1 for heavy armor so 15 +2 with shield +1 if mountain dwarf
High AC would be 11+5+6 so 22 +2 with shield +1 mountain dwarf for AC of 25 max.

Now just make the 'Magic' bonus for armor = Damage Resistance instead of AC.

25 seems like a good max system AC given bounded accuracy goals.

Special cases.
Monk defense = 10 + dex mod + wis mod
Barbarian defense = 10 + dex mod + con mod
Mage armor = 10 + dex mod + int mod when up
None of those combine with each other or any worn armor. You don't get a prof bonus because there is no item to be proficient in.

Bracers of defense work like magic armor and give you DR.
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The tingling means it’s working!
I'd prefer AC (or rather, "how hard it is to hit you with a melee weapon") to be based on the target's skill at fighting. A Dex 10, first level fighter in chain mail should be easier to hit than a Dex 10, twentieth level fighter in chain mail. Shields should give Cover. Armor should protect from damage: some form of DR, such as Resistance to weapon damage, capped at 5 for light, 10 for medium, 15 for heavy. Missile fire should be a straight DC based on size of target, distance, movement, and cover/concealment.

But that's not D&D. :)

Still, I like your proficiency idea. It matches with my desire for the target's skill to influence how hard it is to hurt that target (currently handled by D&D abstractly, via HP rising with level). Using your post as base, my suggestion is to base medium armor on Str, and heavy armor on Con.


But makes the world itself a lot more boring.

The point with having onlyu categories instead of specific armors is that you can then assign relevant specific armors into the different categories, depending on the setting.

Consider Europe around 1100, 1250, and 1400, and 1550 BC

At 1100 AD, light armor is a chain shirt, medium armor is a chainmail hauberk with pot helmet, and heavy armor is a mail shirt, arms, gloves, leggings, coif and a barrel helm, possibly reinforced with plates at knees and armpits.

At 1250 AD, light armor is still a chain shirt, medium armor is chain jacket and pants with metal greaves and vambraces and a bascinet, heavy armor is plate over mail, with the late being separate peices but covering most of the body.

In AD 1400, light armor is a front-only curirass, medium armor is cuirass with conquistador helmet or bascinet and partial leg and arm plates, and heavy armor is full plate.

In A1550, light armor is quite likely again a chain shirt, but this time around fine enough to wear under clothing, medium armor is a front-only breastplate and helm with armored gloves and heavy riding boots, and heavy armor is thick plate half-armor with full helmet.

By having the game describe armor only as light, medium, and heavy we save ourselves the specifics of these different kinds of armor; the exact descriptions become setting details while the game effects remain the same for each category.


Consider Europe around 1100, 1250, and 1400, and 1550 BC

And what when someone wears heavy armor from a previous era? Does it still protect like heavy armor, and thus is as good as the more modern version, or does it suddenly become medium armor with completely different attributes? You also have no way to differentiate different kinds of armor. To use your example, the armor in Europe is as effective as the one in the Middle East or Asia, and the tribes of Africa can even compete with the finest light armor made in France.


Adding proficiency to defenses/armor just negates the point of having bounded accuracy.

How? Saves are basically defenses you roll and they already add proficiency bonus to them.

If you keep the numbers small then you keep bounded accuracy, so if you start AC at 8 like spellcasting DC and add an ability score + proficiency you still have bounded accuracy. 8 + 5 + 6 = 19
Now we can have armor add a small bonus to that or just give DR.

I like the idea of a higher level character having better defense without grinding gear.

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