Magic Damage Reduced

• Magic Damage Reduced applies to any magic and elemental (fire, lightning and cold) damage remaining after Cyclone Armor and then Energy Shield have been applied. MDR applies to each separately, so an attack applying 20 magic, 20 fire, 20 lightning and 20 cold damage would apply no damage after MDR 20 was applied. [1]
• Effectiveness is reduced when applied to magic or elemental damage applied by the following missile attacks:

Damage Rate
41/1024 (~1/25)	82/1024 (~2/25)	205/1024 (~1/5)
Arctic Blast Armageddon fire Fire Wall Firestorm Immolation Arrow pyre Meteor pyre Molten Boulder fire Catapult meteor pyre Countess fire wall Diablo armageddon fire Diablo firestorm Vampire fire wall Vampire meteor pyre	Inferno Wake of Inferno Diablo lightning Fetish Shaman inferno Megademon inferno Salamander fire cloud	Wake of Fire

[2]

• When MDR completely negates magic and elemental damage, it does not matter if Lower Resist, Conviction or -% Enemy Resistance then reduce Resist %, since there is no damage to which Resist % can be applied (although Resist % will still apply to cold length or freeze length).
• A combination of Resist % and Absorb is generally more effective at significantly reducing or negating magic and elemental damage.
• When an attack applies magic or elemental damage and physical damage and MDR > magic or elemental damage, the excess is applied to physical damage after Damage Reduced by % or Damage Resist % has been applied. [3] [4]
• Attack applying 100 physical damage and 50 fire, 50 lightning and 50 cold damage to a target with MDR 100 and DR 50%, would apply no fire (50-100 = -50), lightning (-50) or cold (-50) damage and 50 physical damage before excess MDR (-150 in total) applied: this would result in no (100-150 < 0) damage.

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Helm

Template:D2 Skill bonus |- |7 |align=left|Mal Rune in helm socket |49 |No |- |(1-2) !align=left|Safety helm |13 |No |- |2 !align=left|Howltusk Great Helm |25 |No |- |3 |align=left|Radiance helm |27 |No |- |3 !align=left|Natalya's Totem Grim Helm |59 |No |- |10 !align=left|Hwanin's Splendor Grand Crown |45 |No |- |(10-15) !align=left|Vampire Gaze Grim Helm |41 |No |}

Template:D2 Affix bonus |- |1 !align=left|Circlet of Warding |5 |7 |- |2 !align=left|Circlet of the Sentinel |12 |18 |- |3 !align=left|Circlet of Guarding |19 |26 |- |(4-6) !align=left|Circlet of Negation |35 |42 |- |2 !align=left|Circlet of the Sentinel |18 |24 |- |3 !align=left|Circlet of Guarding |24 |32 |- |(4-6) !align=left|Circlet of Negation |33 |41 |}

Amulet

Template:D2 Skill bonus |- |1 !align=left|Tancred's Weird Amulet |20 |No |- |(1-2) !align=left|Safety Amulet |13 |No |- |10 !align=left|Crescent Moon Amulet |50 |No |}

Template:D2 Affix bonus |- |1 !align=left|Amulet of Warding |5 |7 |- |2 !align=left|Amulet of the Sentinel |12 |18 |- |3 !align=left|Amulet of Guarding |19 |26 |- |(4-6) !align=left|Amulet of Negation |35 |42 |}

Body armor

Template:D2 Skill bonus |- |7 |align=left|Mal Rune in body armor socket |49 |No |- |(1-2) !align=left|Safety body armor |13 |No |- |1 !align=left|Iceblink Splint Mail |22 |No |- |2 !align=left|Berserker's Hauberk Splint Mail |3 |No |- |2 !align=left|Isenhart's Case Breast Plate |8 |No |- |3 !align=left|Greyform Quilted Armor |7 |No |- |3 |align=left|Stealth body armor |17 |No |- |7 |align=left|Rain body armor |49 |No |- |(6-10) !align=left|Que-Hegan's Wisdom Mage Plate |51 |No |- |10 !align=left|Skullder's Ire Russet Armor |42 |No |- |(7-11) !align=left|The Spirit Shroud Ghost Armor |28 |No |- |(5-12) !align=left|M'avina's Embrace Kraken Shell |70 |No |- |(9-13) !align=left|Skin of the Vipermagi Serpentskin Armor |29 |No |- |15 !align=left|Tal Rasha's Guardianship Lacquered Plate |71 |No |- |(10-16) !align=left|Iron Pelt Trellised Armor |33 |No |- |17 |align=left|Prudence body armor |49 |No |- |(15-20) !align=left|The Gladiator's Bane Wire Fleece |85 |No |}

Template:D2 Affix bonus |- |1 !align=left|Body armor of Warding |5 |7 |- |2 !align=left|Body armor of the Sentinel |18 |24 |- |3 !align=left|Body armor of Guarding |24 |32 |- |(4-6) !align=left|Body armor of Negation |33 |41 |}

Missile weapon

Template:D2 Skill bonus |- |(9-13) !align=left|Magewrath Rune Bow |43 |No |}

Axe

Template:D2 Skill bonus |- |(12-15) !align=left|Spellsteel Bearded Axe |39 |No |}

Club

Template:D2 Skill bonus |- |2 !align=left|Stoutnail Spiked Club |5 |No |- |2 |align=left|Black club |35 |No |}

Hammer

Template:D2 Skill bonus |- |2 |align=left|Black hammer |35 |No |}

Mace

Template:D2 Skill bonus |- |2 |align=left|Black mace |35 |No |- |(9-12) !align=left|Moonfall Jagged Star |42 |No |}

Orb

Template:D2 Affix bonus |- |1 !align=left|Orb of Warding |5 |7 |- |2 !align=left|Orb of the Sentinel |12 |18 |- |3 !align=left|Orb of Guarding |19 |26 |- |(4-6) !align=left|Orb of Negation |35 |42 |}

Scepter

Template:D2 Skill bonus |- |1 !align=left|Rusthandle Grand Scepter |17 |No |}

Spear

Template:D2 Skill bonus |- |(1-2) !align=left|Safety spear |13 |No |}

Staff

Template:D2 Skill bonus |- |7 |align=left|Memory staff |37 |No |- |(5-8) !align=left|Ondal's Wisdom Elder Staff |66 |No |- |15 !align=left|Razorswitch Jo Staff |28 |No |}

Sword

Template:D2 Skill bonus |- |3 !align=left|The Patriarch Great Sword |29 |No |- |(7-12) !align=left|Ginther's Rift Dimensional Blade |37 |No |}

Wand

Template:D2 Skill bonus |- |4 |align=left|White wand |35 |No |}

Shield

Template:D2 Skill bonus |- |7 |align=left|Mal Rune in shield socket |49 |No |- |(1-2) !align=left|Safety shield |13 |No |- |1 !align=left|Stormguild Large Shield |13 |No |- |2 !align=left|The Ward Gothic Shield |26 |No |- |5 !align=left|Bverrit Keep Tower Shield |19 |No |- |7 |align=left|Sanctuary shield |49 |No |- |(14-18) !align=left|Gerke's Sanctuary Pavise |44 |No |}

Template:D2 Affix bonus |- |1 !align=left|Shield of Warding |5 |7 |- |2 !align=left|Shield of the Sentinel |18 |24 |- |3 !align=left|Shield of Guarding |24 |32 |- |(4-6) !align=left|Shield of Negation |33 |41 |}

Auric shield

Template:D2 Skill bonus |- |(5-9) !align=left|Alma Negra Sacred Rondache |77 |No |}

Ring

Template:D2 Skill bonus |- |(1-2) !align=left|Safety Ring |13 |No |- |3 !align=left|Nagelring Ring |7 |No |- |(12-15) !align=left|Dwarf Star Ring |45 |No |}

Template:D2 Affix bonus |- |1 !align=left|Ring of Warding |5 |7 |- |2 !align=left|Ring of the Sentinel |12 |18 |}

Boots

Template:D2 Skill bonus |- |1 !align=left|Goblin Toe Light Plated Boots |22 |No |- |(1-2) !align=left|Safety boots |13 |No |}

Belt

Template:D2 Skill bonus |- |(1-2) !align=left|Safety belt |13 |No |- |(10-15) !align=left|String of Ears Demonhide Sash |29 |No |}

Gloves

Template:D2 Skill bonus |- |(1-2) !align=left|Safety gloves |13 |No |}

Set bonus

Template:D2 Skill bonus |- |3 |align=left|Cathan's Traps Full |11 |No |- |15 |align=left|Natalya's Odium 2 items |59 |No |- |10 |align=left|Immortal King Full |76 |No |}

Reference

• A few random questions (Technical Discussion)
• PDR/MDR Overflow Mechanic (Technical Discussion Archives)
• Gustafsson, Tommi, Magic Damage Reduction Modification vs, Frame-Based Attacks