Armor/Old Mechanics

Defense Classes
This mechanic is reworked in version 7.31. Attack and defense classes are now represented through the following abilities:

There are several different classes of armor defense (also known as armor type), which determine how much damage a unit takes against certain attack classes. Each of the 3 different defense classes (Hero, Basic, Structure) either reduces, increases, or does not affect the damage from each of the attack classes, on top of armor values manipulating them.

Attack damage dealt against defense class is defined as



With  being the Attack Damage,   being the Defense Class Damage Multiplier and   being the Damage Multiplier.

The following table shows how much damage each defense class reduces against each attack class, and the unit's defense class (units which take a set amount of damage per attack are excluded).

Examples

 * with 100 damage attacks a siege creep which has 0 armor and deals damage to it. If the siege creep gained 5 armor, how much the 100 damage attack would deal?


 * 's Base Armor for this example is.
 * 's Base Armor for this example is.




 * 's Damage Multiplier is undefined.
 * According to the table values, the attack class multiplier is because the attack class "hero" (from ) deals % less damage against the defense class "structure" (to the Siege Creep).




 * Therefore in this example, 's 100 damage attack to the siege creep with 5 armor would be . The same attack would deal damage to a unit with any other defense class, since attack class hero deals full damage to them.

WC3 DotA Armor

 * In DotA the base magic resistance was bound to the assigned armor. In case of Hero Armor only 75% of the magic damage was applied. Some heroes possessed hidden passive skills to alter their base magic susceptibility albeit Hero Armor to 90% or 65% . Nowadays, in Dota 2 magic resistance works independently from armor.
 * In 6.86 defense classes were renamed and some other classes were removed.
 * The following defense classes were renamed: Unarmored ➜ Soft, Light ➜ Weak, Medium ➜ Basic, Heavy ➜ Strong and Fortified ➜ Structure.
 * Weak and Basic defense classes were removed. Units who previously uses the Weak and Basic defense class now use the Soft and Strong defense class respectively.

Negative Armor Disparity
Amplified damage from negative armor is calculated differently in WC3 DotA than in Dota 2.

Negative armor in WC3 DotA has a cap of -20 armor (71% damage increase). Further reducing the armor does not change the damage increase. Also, the more aggressive damage amplify formula is used resulting in a max damage increase of 71%.

The amplified damage is defined as



With  being the armor value.

 Comparison table