Armor

Armor is an attribute that reduces damage taken to health but not to shields. Not all enemies possess armor: Warframes, most bosses, and all Grineer do, but normal Corpus and Infested enemies do not have any. For a given Warframe, its armor value can be found in the Arsenal. Armored enemies have their base armor values listed in the Codex but this value increases when they spawn with higher levels.

In combat, enemies with more than one point of armor have their health bars displayed yellow instead of red; it is possible to strip away armor value through certain abilities or damage procs, turning those enemies' health bars back to red.

In the Damage 2.0 system, health bars always have a health class (flesh, cloned flesh, etc.) which decrease or increase incoming damage depending on the damage type being inflicted (,, etc.); armored entities have an additional class on their health called their armor class (either ferrite or alloy) that further decreases or increases incoming damage. This additional class is removed if the armor is stripped.

Effects
When damage is inflicted to an armored target, there are two related calculations made.


 * 1) The working armor value of the target is increased or decreased based off the damage type, armor class, and health class of the weapons and entities involved.
 * 2) Incoming damage is reduced by the type-modified armor value according to a damage reduction formula.

Armor Class Modifiers

 * See also: Damage 2.0

There are two classes of armor, Ferrite and Alloy. Both are strong against damage and weak against. Ferrite armor is relatively common with low- and mid-level enemies such as Lancers and Troopers, as well as all Warframes, and has generally weaker resistances than the more advanced Alloy Armor. Alloy Armor is more frequently found on high-level units, like Bombards, Napalm, and bosses.

Damage type modifiers will affect the effectiveness of the target's armor value. They are given by the following equation:

$$\text{Net Armor}=\text{Armor}(1+\text{Armor Class Modifiers})$$


 * Armor is your armor value before considering damage types.
 * Armor Class Modifier can be found on the nearby charts.

Apart from this armor value modification, type damage modifiers against the armor and health classes of the target also plainly multiply the damage. There is a more accurate total damage calculation further down the page, but this section covers the armor value modification.

Damage Reduction Formula


The damage reduction from armor is as follows:

$$\text{Damage Reduction}=\frac{\text{Net Armor}}{\text{Net Armor}+300}$$

A net armor value of 300 will reduce incoming damage by, so only half of the weapon's damage is inflicted in total. At 600, you receive only 33% of a weapon's outgoing damage. At 900 armor, damage is divided by 4, and so on.

Effective Health
Effective health is the concept that each single point of health you have actually absorbs more than one point of damage, so you effectively have more hit points than indicated. Therefore, there are two ways that armor functionality can be imagined: either as a reduction to damage, or as an increase of effective health and incoming heals.



An alternative way to think of armor transforms the above equation to the following:

$$\text{Effective Health}=\frac{\text{Nominal Health}}{1-\text{Damage Reduction}}$$


 * Nominal Health means "health in name", referring to the Health points in your screen's upper right corner.
 * Effective Health is your "health in effect", reflecting a "truer" measurement of survivability.

Example 1: If you have 1000 Nominal Health, 100 armor, and are being attacked with only impact damage, your Effective Health would be:

$$\text{Damage Reduction}=\frac{\text{Net Armor}}{\text{Net Armor}+300}=\frac{100}{100+300}=0.25=25%$$

$$\text{Effective Health}=\frac{\text{Nominal Health}}{1-\text{Damage Reduction}}=\frac{1000}{1-0.25} \approx 1,333$$

Example 2: If you have 1000 Nominal Health, 600 armor, and are being attacked with only impact damage, your Effective Health would be:

$$\text{Damage Reduction}=\frac{\text{Net Armor}}{\text{Net Armor}+300}=\frac{600}{600+300} \approx 0.67=67%$$

$$\text{Effective Health}=\frac{\text{Nominal Health}}{1-\text{Damage Reduction}}=\frac{1000}{1-0.67} \approx 3,000$$

Mods
and increase armor value when equipped along with  when channeling with melee. As a percentage modifier, Warframes with higher base armor values have a higher benefit from it. Like with most other stats, armor gains from mods stack additively together before being multiplied with the Warframe's base armor:

$$\text{Total Armor}=\text{Base Armor}(1+\text{Mod Multiplier})$$


 * Mod Multiplier refers to the value on the mods equipped. It is 1.1 at max rank Steel Fiber, 0.45 at max rank Armored Agility, and 1.55 with both equipped.

Neglecting damage type modifiers, the relative increase in effective health from this mod is exactly proportional to the armor increase. Let us call the effective health, nominal health, and armor E, H, and A respectively and use ΔX to denote the discrete increase in the variable X, then:

$$E=\frac{H}{1-\text{Damage Reduction}}=HR$$

Now we first find the change in E as a result of a change in H, and then the change in E as a result of the change in A. The total change in E is the sum of these two changes:

$$\Delta E = R \Delta H + H \Delta R$$

$$\Delta E = (\frac{300+A}{300}) \Delta H + H \frac{\Delta A}{300}$$

$$\Delta E = (\frac{300+A}{300}) \Delta H + \frac{H}{300}\Delta A$$

Now ignoring any increases in the nominal health (i.e. ΔH=0):

$$\Delta E = \frac{H}{300}\Delta A$$

Since H is a constant we end up with:

$$\Delta E \propto \Delta A$$

Where most algebraic simplification was omitted and to make the notation cleaner, we have set:

$$ R = \frac{1}{1-\text{Damage Reduction}}=\frac{300+A}{300}$$

It is also worth noting that this is only including individual, independent variations in H and A. If we were to vary them at the same time, a different and much more involved analysis has to be carried out.

For example, for Warframes with the common base armor value of 65, a maxed Steel Fiber increases effective health by only about +19.6%, whereas the benefit of a maxed at level 30 is +246.7%. Valkyr, at 600 base armor, still only gets +73.3% out of a maxed Steel Fiber. However, the effective health increases from Steel Fiber apply as gains from sources of healing&mdash;that is to say, increasing armor increases the effective healing received, whereas simply increasing max nominal health does not.

is the equivalent mod for sentinels, while Kavats and Kubrows can increase armor via, as well as via the Kavasa Prime Collar for the latter. Link Armor increases their armor by a percentage of the Warframe's total armor, which means that equipping Steel Fiber or Armored Agility on a Warframe directly increases the armor of its Kavat or Kubrow companion; the Kavasa Prime Collar gives a flat +100 armor bonus.

Arcanes
The Arcane Guardian Arcane Enhancement provides a chance whenever the Warframe receives damage to increase its armor for a short time. It stacks additively with mods:

$$\text{Total Armor}=\text{Base Armor}(1+\text{Mod Multiplier}+\text{Arcane Bonus})$$

Warframe Armor and Effective Health
Unlike health and shield, a Warframe's armor doesn't change as it advances from Rank 0 to Rank 30, with the exception of Nidus. All Warframes have Ferrite Armor and Flesh health. There are currently no effects that remove Warframe armor.

Armor Calculator
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Enemy Armor
Enemy armor values are displayed under the codex and infobox, but scale to the enemy's level. Generally, only Grineer and boss enemies have armor, while the only Corpus and Infested units to posses armor are Bursa units, Oxium Osprey and the Juggernaut. When the enemy health bars is yellow, armor is in effect and damage will be reduced and cause it to flicker red.

Scaling of enemy armor values uses the following formula:

$$\text{Armor}=\text{Base Armor}(1+\frac{(\text{Current Level}-\text{Base Level})^{1.75}}{200})$$


 * Base Armor: Base armor value for the enemy.
 * Current Level: The level of your target enemy.
 * Base Level: This is the initial level an enemy can spawn. This is important because certain enemy types, such as Heavy Grineer, will not spawn until certain levels (like level 8 for Heavy Gunners), so while they may be level 30, their armor has only scaled up 22 times.



As mentioned before, this formula causes high level Grineer (lets say up from level 50) to be very hard to kill, as you can see in the example of a level 108 Heavy Gunner:

$$500(1+\frac{(108-8)^{1.75}}{200})=8405$$

$$\text{Damage Received}=\text{Attack Damage}\times (1-\text{Damage Reduction})$$ $$\text{Damage Received}=\text{Attack Damage}\times (1-0.9655)$$ $$\text{Damage Received}=\text{Attack Damage}\times 0.0345$$

The resulting damage received by the Heavy Gunner is dramatically reduced to ~3.45% of original damage.

Removing Enemy Armor
There are several effects which reduce enemy armor. If a target's armor is reduced to 0, it loses its armor type. As such, damage inflicts significantly more damage to a weakly Ferrite-armored enemy than against one whose armor has ultimately been nullified, since apart from the armor mitigation, the +75% damage bonus is lost.

Corrosive Status Procs
status effects remove 25% of a target's current armor amount, permanently (except in Duels and Conclave, where it only lasts 8 seconds against other Tenno). As a result, each successive proc on the target removes less armor than the previous hit. Even though the armor value should theoretically never hit 0 like this, it does get removed when armor is reduced to below 1, due to rounding.

Focus
For the Tenno who chose the School of Unairu, they will have access to Sundering Dash which allows reducing their enemies' armor.