Lethality vs Armor Penetration in LoL: ⚔️ When to Use Each and Why It Matters ⚡

If you play assassins or AD carries in League of Legends, you have faced this question at some point: should I buy lethality or armor penetration? Both stats help you bypass enemy armor. But how they work is fundamentally different, and picking the wrong one can leave significant damage on the table depending on the game phase and the target you are trying to kill.

This guide explains what each stat does, how the math plays out in practice, when each one is more efficient, and which items provide each option.

What Is Lethality?

Lethality (previously called flat armor penetration) is a stat that subtracts a fixed amount from the target's armor at the moment of the attack. It functions as a direct reduction of the enemy's armor before the damage formula is applied.

Practical example:

• You have 18 Lethality
• The enemy has 40 armor
• The damage calculation treats them as having 40 - 18 = 22 armor

One important rule: Lethality cannot reduce armor below zero. If the enemy has 15 armor and you have 30 Lethality, the game treats them as having 0 armor, not -15.

Another key detail: Lethality scales with your champion's level. At level 1, only 60% of your Lethality is applied. At level 18, 100% of your Lethality is fully active.

What Is Armor Penetration?

Armor penetration (also called "% pen") is a stat that ignores a percentage of the target's armor. Instead of subtracting a fixed value, it treats a fraction of the enemy's armor as if it simply does not exist.

Practical example:

• You have 30% armor penetration
• The enemy has 200 armor
• The damage calculation treats them as having 200 × (1 - 0.30) = 140 armor

Unlike Lethality, percentage armor penetration scales proportionally with the target's armor. The more armor the enemy has, the more damage you gain from % pen.

How Both Stats Interact When You Have Both

When you have both Lethality and % armor penetration, the order of calculation matters:

1. Percentage armor penetration is applied first
2. Lethality is then subtracted from the resulting value

Example:

• Enemy has 200 armor
• You have 30% penetration and 18 Lethality
• Step 1: 200 × (1 - 0.30) = 140 armor
• Step 2: 140 - 18 = 122 armor used in the damage calculation

When Lethality Is Better

Lethality is most efficient when the target has low armor. This happens primarily when:

• Early and mid game: supports, ADCs, and mages rarely have much armor built yet
• Assassinating squishy targets: these champions typically sit at 40 to 80 armor for a large portion of the game
• One-shot builds: when the goal is to eliminate a target before they can react, Lethality delivers the raw burst damage without depending on the enemy's armor being high

Champions that use Lethality well: Zed, Talon, Kha'Zix, Qiyana, Jayce (AD build), Pantheon

When Armor Penetration Is Better

Percentage armor penetration scales better when the target has high armor. It is more efficient in:

• Late game: tanks with 200, 300, or more armor. The % pen removes a proportionally larger slice than flat Lethality
• Anti-tank compositions: when the goal is to cut through the frontline and deal damage to everyone
• ADC in late game: when enemy tanks are fully built

Comparative example against a tank with 250 armor:

Champions that use % armor penetration well: Yasuo, Yone (Last Whisper), ADC with Lord Dominik's Regards, Vayne (Silver Bolts passive)

Comparison Table: When to Use Each

Main Items for Each Stat

Items with Lethality

• Serpent's Fang: Lethality + reduces shields on enemies you damage
• Duskblade of Draktharr: Lethality + burst damage after coming out of stealth
• Youmuu's Ghostblade: Lethality + movement speed active
• Edge of Night: Lethality + a spellshield that blocks the next ability

Items with Armor Penetration

• Lord Dominik's Regards: 35% armor penetration + bonus damage against targets with more max HP than you
• Mortal Reminder: 30% armor penetration + applies Grievous Wounds
• Last Whisper: 20% armor penetration (component item that builds into the above)

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Pro Tips: Lethality and Armor Pen in LoL

• Build Lethality first, % pen later: most assassin builds start with Lethality items in early/mid game and add a % pen item in the late game if enemy tanks are heavily built.
• Check enemy armor before committing to a build path: the scoreboard (Tab) shows enemy items. If the enemy tank already has three armor items in the mid game, consider moving toward % pen earlier than usual.
• Lord Dominik's vs Last Whisper route: if the enemy has high HP in addition to armor, Lord Dominik's wins due to the bonus damage against targets with more HP. If your champion crits frequently, the Last Whisper build path (into Mortal Reminder or Lord Dom's) is typically the correct late-game purchase.

FAQ: Lethality and Armor Penetration

1. Does Lethality work on magic damage? No. Lethality and armor penetration only affect physical damage. For magic damage, the equivalent stats are magic penetration (flat) and percentage magic penetration.

1. Is there an exact armor value where % pen becomes better than Lethality? It depends on how much Lethality you have. In general, % pen starts outperforming Lethality when the target has more than 100 to 150 armor with typical assassin builds.

1. Does Grievous Wounds count as armor penetration? No. Grievous Wounds reduces healing received by the enemy, not their armor. It is a completely separate stat.

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