Armor as Damage Reduction

While the armor and Armor Class system presented in the Pathfinder Roleplaying Game is tried and tested, some players may yet have a sense that it feels slightly off. That is to say, if a suit of armor is actually protecting the wearer from attacks that strike but simply fail to cause the wearer harm, why then do we say that armor reduces the chance of a hit? The abstraction has been clarified in the rules by defining what it means to be “hit” in combat as actually being “hit in such a way as to effectively cause harm,” but this explanation is still not enough for some players.

The following is an alternative system that allows armor to absorb the damage of attacks, rather than a system that provides an abstract way of determining when a hit does actual harm. Like all the rules presented in this chapter, it is a variant to the base system of the Pathfinder RPG. It is for GMs who want armor to reduce damage rather than increase Armor Class, and replaces the normal rules for armor.

In this system, a creatures no longer has an Armor Class. Instead it has a Defense score that a foe's attack roll must meet or exceed to hit the creature. Then any damage is reduced by damage reduction based on the creature's armor worn and any natural armor bonus the creature has. Furthermore, armor has a chance of reducing all critical hits to normal hits, by replacing the confirmation roll for critical hits with a critical defense check made by the creature threatened by the critical hit.

In this alternative system, a creature does not have an Armor Class (AC); it instead has a Defense score. see combat statistics).

Armor as Damage Reduction
Armor in this system keeps all of its normal statistics and qualities, but its armor bonus (including any enhancement bonus added to armor bonus and natural armor bonus) is converted to Damage Reduction. The DR an armor provides is equal to its total armor bonus with a +1 bonus at 5th level or at 5 Hit Dice, with an increase to that bonus of +1 for every five levels above 5th level, or every 5 Hit Dice over 5 Hit Dice (to a maximum of +4 to DR at 20th level or at 20 or more Hit Dice), provided that the creature wearing the armor is also proficient with the armor.

Using Armor without Proficiency: Creatures using armor they are not proficient with do not gain the bonus per level or Hit Dice to the DR, on top of any of the other normal penalties for using armor without proficiency.

Armor DR: This type of DR blocks the damage of all attacks that would normally be affected by DR, based on the composition of the armor (see Table 5–1, below). Unlike most forms of damage reduction, armor DR stacks with other types of DR. For instance, a skeleton possesses DR 5/bludgeoning, a natural armor bonus of +2, and is wearing a non-magical breastplate with an armor bonus of +4. The skeleton's total DR would be 11 against non-magical non-bludgeoning attacks, and 6 against non-magical bludgeoning weapon attacks. Magic weapons and attacks from Large or larger creatures bypass the skeleton's armor-based DR, but not the DR 5/bludgeoning. If the skeleton was attacked by a Large creature with a bludgeoning weapon, its DR would be 0.

DR can vary by location on a creature's body, though. For instance, consider the same skeleton from our previous example. Its breastplate only protects its torso. Non-magical, non-bludgeoning attacks against its chest or vitals would have to overcome DR 11; non-magical, non-bludgeoning attacks against its head, though, would only have to overcome a DR 7 (DR 5/bludgeoning + DR 2/magic).

Natural Armor Bonus and DR: A creature that has both DR from a source other than armor and a natural armor bonus gains the effects of an enhanced form of DR, similar to how the composition of the armor grants special DR/armor defenses. If a creature has natural armor and DR, it takes the best form of the special protection provided by both.

For instance, if a creature has a natural armor bonus and DR/magic, under these optional rules that creature’s DR becomes DR/—, and can be bypassed by Gargantuan or larger creatures. (see Table 5-2, below).

Unusual Creatures and Armor DR: Amorphous or incorporeal creatures have an easier time bypassing armor-based DR. When they attack a creature with armor-based DR, they typically treat that DR as a fraction of its number. Attacks by incorporeal creatures entirely ignore the DR unless that DR comes from a effect or from armor with the ghost touch special armor quality. These traits are detailed in Table 5–3.


Material DR Provided Attacker Size to Bypass DR
Non-magical armor 1 DR/magic Large
Magical armor 1 DR/adamantine Huge
Adamantine armor 1 DR/- Gargantuan

1 Brilliant energy weapons bypass any DR provided by armor. In addition, DR from armor is halved if a creature is grappled or entangled, and does not apply when a creature is helpless or pinned.


Natural Armor/DR DR Provided Attacker Size to Bypass DR
Natural armor DR/magic Large
Natural armor with DR/magic DR/adamantine Huge
Natural armor with DR/adamantine DR/- Gargantuan
Natural armor with DR/- DR/-1 Colossal
Natural armor with DR/epic DR/epic1 n/a

1 A creature that already has DR- or DR/epic increases its DR by an amount equal to its natural armor bonus.


Attacking Creature Type DR Modifier
Amorphous1 x1/2
Incorporeal x0 (unless DR is from a force effect of ghost-touch armor)
Swarm of Tiny creatures x1/2
Swarm of Diminutive creatures x1/4
Swarm of Fine creatures x0

1 Elementals, oozes, oozelike creatures, and any creature with the amorphous defenseive ability (Pathfinder RPG Bestiary 2, pg 294).

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