PoE 2: Penetration Explained

Penetration is a Hit-based mechanic in Path of Exile 2.

A Note for Path of Exile 1 Players:

This mechanic works similarly in Path of Exile 2, but it has one very important difference: Penetration does not work beyond 0% Resistance. You cannot scale your Damage multiplicatively using negative Resistance Penetration like you can in Path of Exile 1.

What is Penetration?

Penetration is a mechanic that causes a Hit to deal Damage that bypasses the target's Resistance by a stated amount.

Note: Penetration only interacts with Hit Damage. It does not interact with Damage over time in any way.

Penetration will typically be tied to a specific Resistance type such as the Lightning Penetration Support gem, which will make Damage from Hits with the supported Skill Penetrate 30% Lightning Resistance. For example a Hit of 1000 Lightning Damage against a target that has 50% Lightning Resistance would usually deal 500 Damage after Resistance mitigation. If the attacker had 30% Lightning Penetration, the defender would mitigate the Lightning Damage as though they had 20% Lightning Resistance, and would therefore take 800 Damage after Resistance mitigation.

Note: although the Damage from Ailments is based on Hit Damage, this is calculated pre-mitigation and therefore does not include Penetration.

Penetration isn't always tied to a single type of Damage. Similar to other mechanics, Penetration can sometimes be grouped together into Elemental Penetration, which causes all Fire, Cold and Lightning Damage dealt with Hits to bypass the target's Resistance of those types by the stated amount.

Penetration Cap

Penetration cannot apply to Resistance below 0%. The method of reaching 0% Resistance or lower is not relevant; please see the below examples.

Example 1: Over Penetration

You have The Pandemonius equipped, granting you have 75% Cold Penetration. You deal a Hit of Cold Damage to a target that has 50% Cold Resistance. The Cold Damage Penetrates all of their Cold Resistance and the target takes Damage as though they had 0% Cold Resistance. In this example, 25% of the Cold Penetration is essentially wasted, as it cannot go beyond 0%.

Example 2: Lowering Resistance

You have The Pandemonius equipped, granting you have 75% Cold Penetration. You use a combination of Elemental Weakness and the Exposure from Frost Bomb to lower the target's Cold Resistance by a total of 54%. Note that these methods of lowering Resistance are not Penetration, and can bring Resistance below 0% into the negatives. The target has 50% Cold Resistance, which is lowered to -4%. You deal a Hit of Cold Damage to the target. The target takes Damage based on having -4% Cold Resistance, making them take 4% more Damage than the original total Cold Damage of the Hit. In this example, all of the Cold Penetration is wasted, as it cannot go beyond 0%.

Penetration vs Lowering Resistances

Due to being unable to Penetrate Resistance below 0%, you must decide the more beneficial approach to dealing Damage. Whilst Exposure, Curses and other similar mechanics can combine to lower a target's Resistance into the negatives and make them take more Damage, you also need to actively utilise those Skills to apply and potentially maintain those Debuffs on targets. Meanwhile Penetration is available in relatively large quantities, such as Breath of Fire which combined with the two small Passive nodes leading to it, provide a total of 27% Fire Penetration. Penetration has the benefit of applying to your Hit Damage without the need to use additional Skills.

Notably you can benefit from both options, for example using Elemental Weakness to first lower a target's Fire Resistance and then utilising an amount of Fire Penetration to bypass the remaining Resistance and deal Damage as though the target had no Fire Resistance.

Note: as Penetration is tied to a Hit of Damage, it is always applied after lowering Resistances using methods such as Exposure, as these are Debuffs that persist on the target. This means that you cannot benefit from Penetration and also utilise negative Resistances on a target, as the two are mutually exclusive.

Leopold's Applause

The Unique Gloves Leopold's Applause make your hits Penetrate all Elemental Resistances by 10%. However, these Gloves also have the special modifier 'Your Hits can Penetrate Elemental Resistances down to a minimum of -50%', which is currently the only way to Penetrate below 0% Resistance. Providing you have enough Penetration, you'll be able to deal Damage with Hits as though the target had -50% Resistance, effectively making them take 50% more Damage.