Physical Resistance Rating

Overview
Physical Resistance Rating (abbreviated PRR) is a form of damage mitigation was that introduced with Update 14.

It provides a percentage reduction in physical damage (bludgeoning, slashing, and piercing), and is granted through multiple sources (items, feats, enhancements) and stacks with itself. Multiple effects granting an Enhancement bonus to Physical Resistance do not stack. Character sheets show the Physical Resistance Rating of the player next to the elemental resistances.

PRR is applied after damage reduction. The PRR is applied to the damage that passes through the DR and is always rounded down. As such If a player would take 20 damage before DR or PRR and has 10 DR and 60 PRR (37.5% reduction), the result is:
 * (20 - 10) * 37.5% = 3.75 rounded down to 3
 * 3 damage is resisted

Note: Monsters and enemies, regardless of their cosmetic armor appearances, don't have PRR.

Formula
The formula for calculating damage mitigation for physical damage was changed in Update 23. The new formula is: 100/(100+Rating)

Example: A character is hit for 100 points of damage.
 * 0 PRR takes full damage, 100 points.
 * 20 PRR takes 16.67% less damage, 83 points.
 * 100 PRR takes 50% less damage, 50 points.

Items

 * Physical Resistance Rating offered by armor type:
 * Cloth armor: 0
 * Light armor: 12 + BAB/2
 * Medium armor: 24 + 2/3*BAB
 * Heavy armor: 36 + BAB
 * Physical Resistance Ratings offered by shield type:
 * Bucklers/Orbs: 0
 * Small shields: 5
 * Large shields: 10
 * Tower shields: 15
 * Bonuses from armor proficiency (This is in addition to the PRR bonus based on armor type):
 * Heavy Armor gives you Physical Resistance Rating equal to your Base Attack Bonus +6.
 * Medium Armor gives you Physical Resistance Rating equal to 2/3 of your Base Attack Bonus (round up) and add +4.
 * Light Armor gives you Physical Resistance Rating equal to 1/2 of your Base Attack Bonus (round up) and add +2.
 * Adamantine Body gives you Physical Resistance Rating equal to your Base Attack Bonus +6.
 * Mithral Body gives you Physical Resistance Rating equal to 1/2 of your Base Attack Bonus (round up) and add +2.
 * Enhancement bonus: items with the Sheltering enchantment or items augmented with a Sapphire of Physical Resistance
 * Artifact bonus: Planar Focus of Prowess grants 15 physical resistance when in a set with a Planar Conflux.
 * Insight bonus: item with Insightful Sheltering
 * Luck bonus: Unbreakable Adamancy set bonus

Feats

 * Shield Mastery increases the Physical Resistance Rating by 3 when using a buckler or small shield, 5 when using a large shield, or 10 when using a tower shield.
 * Improved Shield Mastery increases the Physical Resistance Rating by 5 when using a buckler or small shield, 10 when using a large shield, or 15 when using a tower shield. (Substitute the values of Shield Mastery, do not stack with it.)
 * Two Weapon Defense increases your Physical Resistance Rating by 5 when you wield two weapons (This bonus does not apply when fighting unarmed/with handwraps).

Monk Stances

 * Lesser Mountain Stance improves the Physical Resistance Rating by 3.
 * Mountain Stance improves the Physical Resistance Rating by 8.
 * Greater Mountain Stance improves the Physical Resistance Rating by 12.
 * Ultimate Mountain Stance improves the Physical Resistance Rating by 15.

Bladeforged enhancements

 * Communion of Warding +4/+8/+12 Physical Resistance Rating

Eldritch Knight enhancements

 * Improved Shield improves the Physical Resistance Rating by 3/6/10 while under the effects of the Shield spell.

Pale Master enhancements

 * Bone Armor improves the Physical Resistance Rating by 3/6/10 while under the effect of Shroud of the Zombie, Vampire, or Lich.

Ravager enhancements

 * Ritual Scarring improves the Physical Resistance Rating by 1/2/3.

Sacred Defender enhancements

 * Sacred Defense: +10 Physical Resistance
 * Improved Sacred Defense - Durable Defense: When in Sacred Defense, you gain +5/+10/+15 Sacred bonus to Physical Resistance Rating.
 * Harbored by Light: You gain +10/15/25 Physical Resistance Rating.

Shintao enhancements

 * Iron Skin improves the Physical Resistance Rating while under Mountain Stance by 5/10/15.
 * Meditation of War improves the Physical Resistance Rating while under Mountain Stance by 10.

Stalwart Defender enhancements

 * Stalwart Defense stance improves the Physical Resistance Rating by 10.
 * Improved Stalwart Defense - Durable Defense improves the Physical Resistance Rating while on Stalwart Defense Stance by additional 5/10/15.

Tempest enhancements

 * Improved Parry improves the Physical Resistance Rating by 3/6/10 while dual-wielding.

Warchanter enhancements

 * Rough and Ready improves the Physical Resistance Rating by 2/4/6.
 * Ironskin Chant provides +6 Music bonus to everyone around
 * Warmaster (capstone): +15 Music bonus to single ally

Warpriest enhancements

 * Wall of Steel +3/+6/+10 Physical Resistance Rating
 * Sanctuary For 20 seconds, you gain +20 Sacred bonus to Physical Resistance. (Activation Cost: 10 Spell Points. Cooldown: 1 minute)

Epic Destinies

 * Legendary Shield Mastery, an Unyielding Sentinel's tier 2 ability, improves PRR by 5 per rank when wearing a shield. 3 ranks total, higher ranks require (Improved) Shield Mastery.
 * Heed No Pain, the Unyielding Sentinel's level 4 innate ability, improves PRR by 10 and grants 20 additional physical resistance while in Unbreakable stance.
 * Improved Combat Expertise, a Legendary Dreadnaught's tier 2 ability, improves PRR by 20 when Combat Expertise is active.
 * Sigil of Spell Warding, a Magister tier 1 ability, improves PRR by 15 while it is active and you are standing inside it.
 * Standing with Stone, a Grandmaster of Flowers tier 4 ability, improves PRR by 5 points per rank (3 ranks), if you have Monk levels and are in Mountain stance.