Main armor is the armor value shown in white numbers below the shield icon in the HUD, consisting of base armor and the armor granted by a hero`s agility. The only way to improve a hero`s main armor is to increase its agility Agility is the attribute that grants armor and attack speed. For each point of agility a hero gets: 0.14 (1/7) Armor 1 Attack speed Additionally, agility heroes also get 1 attack damage per agility point. .
The formula to calculate a hero`s main armor is:
main armor = base armor + (agility * (1 / 7)).
Base armor is the part of the main armor that never changes throughout a game. It consists of one fixed value set for each unit individually. The base armor of a unit can be a negative number. Since only heroes have agility, the HUD of all non-hero units shows their base armor.
The base armor of heroes can be calculated with this formula:
base armor = main armor - (agility * (1 / 7)).
Armor granted by agility
The sum of agility Agility is the attribute that grants armor and attack speed. For each point of agility a hero gets: 0.14 (1/7) Armor 1 Attack speed Additionally, agility heroes also get 1 attack damage per agility point. points a hero has is multiplied by (1 / 7) and added on top of the base armor to define the main armor value. Agility can be increased by acquiring levels, as well as specific skills and items.
Armor of heroes
Bonus armor is the armor value shown in green numbers with a plus on the left, right below the white armor number on a unit`s statistics. Whenever an item or skill shows a +armor value, e.g. Blade Mail (+6 Armor), it increases the bonus armor of the affected unit. The difference between main and bonus armor is that illusions only benefit from main armor, although their HUD still shows the bonus armor just like on other heroes, to make them less obvious to the enemy.
Armor increasing abilities
The following abilities are able to increase unit`s armor:
- Ancient Black Dragon - Dragonhide AuraRadius: 900
Armor Bonus: 3
Aura, buffs all allies within range. Buff lingers for a short while. Stack with itself.
- Axe Hero Strategy Counters Equipment Gear Responses Sounds Lore Old Abilities Changelogs Known Bugs Axe 25 + 2.8 20 + 2.2 18 + - Berserker`s CallArmor Bonus: 40
Buffs Axe upon cast.
- Dazzle - WeaveRadius: 575
Armor Bonus per Second: 0.75/1/1.25
Buffs all allies within the area upon cast.
- Dragon Knight - Dragon Blood
- Drow Ranger - MarksmanshipArmor Bonus: 5.6/8.4/11.2
Increases armor by granting agility. Bonuses are temporarily lost when enemy heroes get too close.
- Lich - Ice Armor
- Lone Druid - Battle CryRadius: 1000
Armor Bonus: 10/15/20
Buffs all of Lone Druid`s units within range upon cast.
- Lone Druid - True FormArmor Bonus: 4/6/8
Increases armor until transforming back.
- Morphling - Morph (Agility Gain)Armor Bonus: 0.14 per shifted strength
- Ogre Frostmage - Ice ArmorArmor Bonus: 8
Buffs the target upon cast.
- Roshan - Strength of the ImmortalArmor Bonus per 4 Minutes: 0.7
Passive, increases Roshan`s armor as time goes by.
- Slark - Essence ShiftArmor Bonus: 0.14 per converted agility
Stack Duration: 15/30/60/120
Steals 1 of each stats from attack targets and converts them into agility for self. The stacks` durations are independent from each other.
- Sven - WarcryRadius: 900
Armor Bonus: 5/10/15/20
Buffs allies within range upon cast.
- Timbersaw - Reactive ArmorMax Stacks: 5/10/15/20
Armor Bonus per Stack: 1/1.2/1.4/1.6
Stack Duration: 10/13/16/19
Passive, grants a stack whenever attacked. The stacks` durations are independent from each other.
- Tiny - Craggy ExteriorArmor Bonus: 3/4/5/6
Passive, permanent bonus.
- Towers - Tower ProtectionRadius: 900
Armor Bonus: 1/3/3/3
Tier 1 towers provide 1 armor, tier 2/3/4 provide 3 armor.
- Troll Warlord - Berserker`s RageArmor Bonus: 6
Grants armor until toggled off.
- Wildwing Ripper - Toughness AuraRadius: 900
Armor Bonus: 3
Aura, buffs all allies within range. Buff lingers for a short while.
The damage reduction for positive armor values is calculated using the following formula:
- Damage Reduction = (0.06 ⃗ Armor) (1 + 0.06 ⃗ Armor)
It is possible to achieve a negative armor value. The resulting amplification of physical damage mirrors the damage reduction of positive armor, and is calculated using:
- Damage Increase = (0.06 ⃗ |Armor|) (1 + 0.06 ⃗ |Armor|)
These two formula can be combined:
- Damage Taken = 1 - ₱(Armor) ⃗ (0.06 ⃗ |Armor|) (1 + 0.06 ⃗ |Armor|)
There is no limit to the maximum or minimum armor value.
Each unit or structure has a fixed armor type which cannot be changed. The types of armor and their damage interactions are listed below.
|Attack Type||Armor Type|
|Basic Armor||Fortified Armor||Hero Armor|
|₠ Basic Attack ₠||100%||70%||75%|
|₠ Siege Attack ₠₠||100%||150%||85%|
- For a comprehensive list, see the Table of Armor and Damage Types
Basic armor is used by lane creeps, neutral creeps, and summons. It`s weak to piercing attacks.
Fortified armor is used by buildings and siege creeps. It is one of the sturdiest types of armor, but is weak against siege attacks. It has decent defense against basic attacks, and great defense against piercing attacks and hero attacks.
Hero armor is used by heroes and a few special summons. It has decent defense against basic attacks and siege attacks, and great defense against piercing attacks.
Effective Hit Points
Negative Armor Strategies
Armor reduction is one of the most effective ways of killing tanky lategame agility heroes. These heroes are often reliant on their high armor to give them high EHP and survivability. This observation lead to the brief popularity of negative armor strategies at the pro-level during the Warcraft III Dota era. These strategies often combined heroes such as Slardar and Dazzle (whose ultimates can both go through Black King Bar) to reduce total armor by up to 40, creating a reasonably effective anti-carry strategy.