*Lethality*redirects here. For the 2013 Mastery, see Lethality.

**Armor penetration** is a champion statistic that dictates how much of the target's armor will be ignored when the user deals physical damage. **Percentage armor penetration** and **Lethality** have no effect if the target's armor is less than or equal to 0.

**Armor reduction** is an effect that reduces the target's armor by an amount or percentage for a period of time. **Flat armor reduction** can reduce the value below 0, **percentage armor reduction** cannot.

It is important to note that **penetration** *treats* the target's resistances as being multiplied by a percentage or reduced by a flat amount, in contrast to **reduction** which applies to the target's resistances as a whole.

All champions have 0 base armor penetration and lethality, but they can be increased with items, runes, and some champion abilities.

**Lethality** is the champion statistic that replaced **flat armor penetration**, being introduced in V6.22. It is a stat that essentially converts to *flat armor penetration* at a rate that increases based on the champion's level, in contrast to the former stat which contributed to its full value at all levels. View the formula below for more details.^{[1]}

## Order of calculations

Armor penetration and armor reduction are considered in the following order:^{[2]}

- Armor reduction, flat
- Armor reduction, percentage
- Armor penetration, percentage
- Armor penetration, flat (via Lethality)

**Base** armor and **bonus** armor are calculated separately.

## Flat armor reduction

The target's armor is reduced by an amount. Flat armor reduction stacks additively and is distributed proportionally between base armor and bonus armor.

*Example: 30 armor reduction against a 20 base armor and 40 bonus armor target will reduce base armor by 10 and bonus armor by 20, so the target will be reduced to 30 armor ((20 − 10)*+*(40 − 20) = 30*)*.*

Flat armor reduction can reduce a target's armor below zero. For example, if an enemy with 10 armor has their armor reduced by 25, the enemy will have −15 armor.

## Percentage armor reduction

The target's armor is multiplied by a percentage (100% − the listed reduction). Applies to both base and bonus armor. Percentage armor reduction stacks multiplicatively and is ignored if the target's armor is 0 or less.

*Example: 30% armor reduction multiplies the target's armor to 70%, so a target with 20 base armor and 40 bonus armor will be reduced to 42 armor ((20 × 0.7*) + (*40 × 0.7*)*= 42).*

Percentage armor reduction reduces more armor on targets with higher armor. For instance, with 40% armor reduction, a target with 200 armor will lose 80 while a target with only 50 armor will lose 20.

With 40% armor reduction, the physical damage dealt to a target with 50 armor is only increased by around 15%, whereas the physical damage dealt to a target with 200 armor is increased by around 36%.

## Percentage armor penetration

The target's armor is treated as being multiplied by a percentage for purposes of damage calculation (100% − the listed penetration). Percentage armor penetration stacks multiplicatively and is ignored if the target's armor is 0 or less.

*Example: 30% armor penetration causes the target to take damage as if its armor was multiplied by 70%, so a target with*20 base armor and 40 bonus armor will be treated as though it had 42 for purposes of damage*(the target's actual armor value will not change, however)*(*(20 × 0.7*)*+*(40 × 0.7) = 42).

Because the target's actual armor value does not change, anything else depending on that value also doesn't change.

Percentage armor penetration reduces more armor on targets with higher armor. For instance, with 40% armor penetration, a target with 200 armor will be considered as having 80 less while a target with only 50 armor will be considered as having 20 less.

It should be taken into account that the increase in damage however is not vast, due to the diminishing returns of armor at higher levels. With 40% armor penetration, the physical damage dealt to a target with 50 armor is only increased by around 15%, whereas the physical damage dealt to a target with 200 armor is increased by around 36%.

### Percentage bonus armor penetration

Percentage armor penetration that applies only to **bonus** armor.

*Example: 30% bonus armor penetration multiplies the target's bonus armor to 70% without affecting base armor, so a target with 20 base armor and 40 bonus armor*will be treated as though it had 48 for purposes of damage calculation (the target's actual armor value will not change, however).*(20*+ (*40 × 0.7*)*= 48).*- If the unit has multiple sources of percentage bonus penetration, they stack multiplicatively:
*Example: 10% armor penetration and 30% bonus armor penetration*.*(20 × 0.9))*+ (*40 × 0.7 × 0.9)*)*= 43.2).*

Because the target's actual armor value does not change, anything else depending on that value also doesn't change.

Percentage bonus armor penetration reduces more armor on targets with higher **bonus** armor, but will not have an effect against base armor. For instance, with 40% **bonus** armor penetration, a target with 200 **bonus** armor will be considered as having 80 less while a target with only 50 **bonus** armor will be considered as having 20 less. In contrast, a target with any amount of base armor and no **bonus** armor will be considered as having the same value.

## Lethality

**Lethality** is the statistic that represents flat armor penetration. It grants flat armor penetration using the following formula:

**Flat Armor Penetration**= Lethality × (0.6 + 0.4 × level ÷ 18)

According to the formula, Lethality grants 62.22% − 100% (based on level) of its value.

The target's armor is treated as being reduced by an amount for purposes of damage calculation, but cannot be reduced below 0. Flat armor penetration stacks additively.

*Example 1: 20 lethality on a user at level 18 will cause a target to take damage as if its armor was 20 less, so a target with 30 armor will be treated as though it had 10 for purposes of damage calculation (the target's actual armor value will not change, however).*

Because the target's actual armor value does not change, anything else depending on that value also doesn't change.

**Lethality**has a gold value of 31.45 per point, for more details see this page.

## Examples

Given 10 flat armor penetration and 45% bonus armor penetration, and the target is affected by 30 flat armor reduction and 30% armor reduction;

- Target A has 300 armor (100 base and 200 bonus armor).
- The 300 is reduced to 270 (90 base and 180 bonus armor) by the 30 armor reduction.
- The 270 is reduced to 189 (63 base and 126 bonus armor) by the 30% armor reduction.
- The 189 is considered to be 132.3 (63 base and 69.3 bonus armor) by the 45% bonus armor penetration.
- The 132.3 is considered to be 122.3 by the 10 armor penetration.
- Target A takes damage as if it has 122.3 armor.

- Target B has 18 armor.
- The 18 is reduced to −12 by the 30 armor reduction.
- The −12 is not affected by any further calculations because it is less than 0.
- Target B takes damage as if it has −12 armor.

## Lethality as scaling

The following have their stats improved based on the amount of lethality acquired:

### Champion abilities

- , , , and

## Increasing lethality

### Champion abilities

### Items

This table is automatically generated based on the data from Module:ItemData/data.

#### Item passives

- ( )

### Runes

## Increasing percent armor penetration

### Champion abilities

### Monsters

### Items

This table is automatically generated based on the data from Module:ItemData/data.

Item | Cost | Amount | Availability |
---|---|---|---|

1450 | 20% | All maps | |

3000 | 35% | All maps | |

3200 | 30% | All maps |

#### Item passives

- ( )
- ( )

### Other

## Reducing armor

### Champion abilities

- Percentage Reduction

- (Empowered)

- Flat Reduction

### Items

- Percentage Reduction

### Monsters

- Flat Reduction

## Notes

- Armor penetration will apply to any and all sources of physical damage.
- It will apply to the damage dealt to almost every type of unit, including turrets but not other structures (Inhibitors are the only building with armor).

- Armor reduction will affect the physical damage from any unit source.
- Percentage penetration is applied before flat penetration.
- Turrets and have 30% armor penetration.

## Trivia

- Since armor has a gold value of 20 per point, each point of Lethality lowers the gold value of a target's armor by 12 to 20. This gold value leads to a difference of 7 to 15 per point.

The highest amount of *lethality* any champion can obtain is **120**.

**Runes:**- - 7

**Items:**- Mythic Bonus - 25 (from 5 Legendary items stated below)

- 26
- - 18
- - 12
- - 12
- / / - 10
- / / - 10

**Relevant mathematics:****Items**= + 25 + + + + ( / / ) + ( / / ) = 113 lethality**Runes**= = 7 lethality**Total Lethality**=*113*+*7*=**120**- This is further increased to
**147**lethality with when is included in the equation (113 + 27 + 7 =**147**), which grants 27 lethality when lethality is fully leveled. This is the highest amount of lethality in the game that only can obtain.

- This is further increased to

The highest amount of percentage armor penetration any champion can obtain is **51.25%**.

**Items:**- - 35%
- Mythic Bonus - 25% (from 5 Legendary items, includes )

/

**Relevant mathematics:***(1 -*× )*(1 - 0.25)*=*0.4875**1 - 0.4875*=**51.25%**armor penetration

- The highest amount obtainable in the game is
**68.3125%**with when (max rank) is included in the equation.**Relevant mathematics:***(1 -*× )*(1 -*× )*(1 - 0.25)*=*0.316875**1 - 0.316875*=**68.3125%**armor penetration