In this article, we’ll be looking at exactly how armor functions and how it interacts with additional physical damage reduction.
What Is Armor?
Armor is a defensive stat in Path of Exile that is typically found on the gear that you can equip and is also granted by the Determination aura.
Therefore, if your budget is sufficient, try to buy POE Currency to get or craft more excellent weapons, claws or other items. In this way, you can defeat various monsters and bosses more easily.
Firstly, we need to mention that if you have armor, the physical damage reduction shown on your character sheet is completely redundant. That’s because the physical damage reduction provided by armor is scaled based on the total damage of the hit compared to the total armor of the defender.
For example, if you have ten thousand armor and you take a hit of 1000 damage, the armor would prevent 66% of the damage. But with the same 10,000 armor when you take a hit of 2000 damage, the armor only prevents 50% of the damage.
Notice that the armor in this example prevented less damage against the larger hit. For this reason, armor is much more effective against numerous smaller hits rather than a few larger hits.
Let’s take a look at the calculation for damage reduction from armor. This equation represents the physical damage reduction provided by armor, where AR is the total armor of the defender and damage is the total physical damage of the hit that is taken.
Let’s take the example from earlier. We have 10,000 armor and we’re taking a hit of one thousand physical damage. If we plug the numbers into the equation, we can calculate the damage reduction of 0.66 recurring. We can then multiply this by the original 1000 damage taken to work out the actual damage we are mitigating, which is 667 damage or reduction of 66%.
But what about when we take a much larger hit? Let’s say we still have ten thousand armor, but this time we’re taking a hit of five thousand physical damage.
Plugging those numbers into the equation, we can see that the damage reduction is much lower this time because our armor is lower comparatively with the damage of the hit that we are taking. We mitigate 1429 of the original 5000 damage or a reduction of about 28.5%.
Armor Only Works VS Physical Hits
It’s really important to mention here that by default. Armor only prevents physical damage from hits.
In Path of Exile, many of the enemies will deal multiple types of damage in a single hit. When this happens, armor will only interact with the physical damage portion of the hit.
For example, if an enemy dealt a hit of two thousand physical damage, but 50% of their physical damage was converted to lightning damage, the hit would deal 1000 physical damage and 1000 lightning damage. The armor calculation would then apply to the 1000 physical damage that was taken from the hit.
Armor VS DoT
Armor doesn’t interact with damage over time in any way. So, physical damage taken from things like Bleeding will not be reduced because it deals with physical damage over time.
What Is Additional PDR?
So, what about additional physical damage reduction? This is a stat that is typically found on gear (which you can get by using specific POE orbs), such as strength and strength hybrid body armors and shields. It’s also found on endurance charges and the buff that’s provided by Summon Chaos Golem.
Unlike armor, this stat provides a fixed percentage of physical damage reduction that isn’t affected by differing amounts of damage taken.
In other words, this modifier provides the exact amount of reduction that it displays regardless of how much physical damage you are taking.
Armor & Additional PDR Calculation
But how does additional physical damage reduction interact with armor?
The calculation for armor is applied to the total physical damage taken from the hit to work out the percentage of reduction that armor will provide.
Once that’s calculated, any additional physical damage reduction is then added to the total percentage reduction that armor will provide to work out the total amount that the hit will be reduced by.
Here’s an example. Let’s say we have 25,000 armor and three endurance charges. Each endurance charge provides 4% additional physical damage reduction, so that’s 12% additional physical damage reduction. We take a hit of 4,000 damage.
Firstly, let’s calculate the physical damage reduction provided by armor. Our armor alone will provide 55.5% damage reduction. But before the calculation takes place, we need to add our additional physical damage reduction from the endurance charges we have.
The total physical damage reduction from our armor and endurance charges combined is 67.5%. We can then multiply the damage of the hit against our calculation to work out the total amount of mitigated damage. You can begin to see the value of additional physical damage reduction when combined with armor and POE Currency, especially against larger hits.
Additional PDR VS DoT
It’s worth noting that additional physical damage reduction also applies to damage over time, unlike armor. Physical damage over time, like Bleeding, will be reduced by your total percentage of additional physical damage reduction.
An important note here is that you cannot exceed 90% total physical damage reduction at this part of the calculation, as that is the hard cap.
There is currently no way in the game to increase this cap that means that the total damage reduction of armor alone or additional physical damage reduction alone or a combination of both can never exceed 90%.
However, this doesn’t mean that you can’t reduce physical damage that you take by more than 90%. For example, you could have a total of 90% physical damage reduction to reduce a hit and then further reduce the damage you take with a modifier, such as Fortification.
Armor VS Other Damage Types
It should be mentioned that there are a handful of modifiers in the game that will make armor prevent another kind of damage.
Transcendence is a keystone that applies the armor calculation to elemental damage instead of physical damage whilst also applying a heavy maximum resistance Penalty.
Doryani’s Prototype body armor will prevent your lightning resistance from reducing the damage you take, but instead apply the armor calculation to lightning damage taken.
There’s also the Juggernaut’s Unbreakable node that applies a small percentage of armor and POE Currency buy to elemental damage taken. But in this case, your armor still retains its original function, too.
Lastly, be aware that Overwhelm exists in Path of Exile. This is a modifier that essentially allows the attacker to bypass the stated amount of physical damage reduction.
For example, if a monster had 15% Overwhelm in your calculation of total physical damage reduction to the mobster’s hit was 60%, the monster would hit you as if you had 45% physical damage reduction.
Importantly, Overwhelm cannot go into negative physical damage reduction if it would bypass zero percent unlike the similar mechanic resistance penetration.