Damage is displayed as a red section on a champion's health bar.
- Note: Not to be confused with attack damage, a champion statistic, nor health costs.
Damage is the deduction of a unit's current health as a result of an offensive interaction. It is a property of autoattacks, abilities, on-hit effects and spell effects in League of Legends.
Archetypes
- Ability damage
Ability damage is the damage type inflicted by almost all abilities. 
Fizz's 
Urchin Strike is noteworthy for applying both basic attack damage AND ability damage.
- Ability damage will apply spell effects, including spell vamp.
- Some abilities grant the champion bonus ability damage on their attacks, such as
Righteous Fury. As a standard, however, most effects that trigger on a champion's basic attacks (including those sourced from an ability) deal on-hit damage. - Some abilities modify the champion's attacks to deal ability damage, such as Devastating Blow.
- Most spell effects inflict ability damage, allowing them to trigger other spell effects (excluding itself).
- Basic attack damage
Basic attack damage is the classification for the damage dealt by almost all basic attacks with the notable exceptions being a handful of champion summoned units, such as 
Azir's 
Soldiers.
- Basic attacks will trigger on-hit effects once. Some abilities and items can increase this.
- Basic attack damage will apply life steal.
- Some abilities modify the amount of basic attack damage dealt, such as Hextech Munitions, Powder Keg and Sheen.
- Bleed damage
Bleed damage is the classification for many of the game's lesser damage over times, which are in most cases attached to a basic attack but is also applied by some spell effects. Examples include: 
Deadly Venom and 
Crest of Cinders.
- Bleed damage applies neither on-hit effects, life steal nor spell effects.
- On-hit damage
On-hit damage is the classification for the damage dealt by on-hit effects, which are effects that trigger when a basic attack hits. Examples include: 
Bio-Arcane Barrage and 
Wit's End.
- On-hit damage applies neither on-hit effects, life steal nor spell effects.
- Splash damage
Splash damage is the damage type applied by some area of effects, namely those attached to a basic attack. Examples include: 
Gangplank's 
Powder Keg, 
Jinx's 
Fishbones and 
Nocturne's 
Umbra Blades. Note that not all area of effects that occur on basic attacks are classified as splash damage, such as 
Righteous Fury, which is classified as ability damage.
- Splash damage applies neither on-hit effects, life steal nor spell effects.
Subtypes
- Resistance types
- Physical damage: a type of damage that champions' autoattacks, some abilities, minions, and turrets deal. Armor reduces incoming physical damage. Some effects, such as The Black Cleaver and Elixir of Wrath, are triggered by all sources of physical damage.
- Magic damage: a type of damage that most abilities, items, and on-hit effects deal. Magic resistance reduces incoming magic damage. Some effects, such as Morellonomicon, are triggered by all sources of magical damage.
- True damage: a type of damage that some abilities and on-hit effects deal. This damage cannot be reduced and always does exactly the value stated, although can be blocked by invulnerabilities and health shields.
- Pure damage: a type of damage that is identical in most respects to true damage but will also ignore invulnerability and revive effects. It is exclusive to the Nexus Obelisk
- Critical damage
Critical damage is an additional tag applied to critical strikes and some abilities, such as 
Frostbite. Critical damage will be reduced by 
Randuin's Omen, triggers Template:Cctip, as well as the highest instance of critical damage being tracked in the post-game stats.
- Pet damage
Pet damage is an additional tag applied to the damage inflicted by champion summoned units. This is in addition to any other classifications. For example, the damage dealt by Template:Moi' basic attacks and aura are both classified as "pet damage" in addition to basic attack damage and ability damage, respectively. This classification is currently only used by 
Rylai's Crystal Scepter.
Damage Calculation
The Math of League of Legends is very complex, but doing some experiments, here are some formulas to get the damage of a basic attack:
Without Armor Penetration: (AD/100)(100-ArmorPercentage) With Armor Penetration: (AD/100)(100-((ArmorPercentaje-ArmorPenetrationPercentaje)/100*ArmorPenetrationPercentaje)))
Where:
AD = Attack Damage
ArmorPercentage = The Damage Reduction Percentage(You can see it when the cursor is on armor statistic)
ArmorPenetrationPercentage = The Armor Penetration Percentage(You can see it when activating advanced statistics)
Example:
1st Formula:
We have a champion with
94 Attack Damage
0 Armor Penetration
We attack an enemy with
15 Armor -> 13% Damage Reduction
We use the formula:
(94/100)(100-13) = 81
We are going to deal 81 damage to the enemy. (TESTED IN-GAME)
2nd Formula:
We have a champion with
101 Attack Damage
30% Armor Penetration
We attack an enemy with
15 Armor -> 13% Damage Reduction
We use the formula:
(101/100)(100-((13+30)/100*30)) = 87
We are going to deal 87 damage to the enemy. (TESTED IN-GAME)
NOTE:
The League of Legends math is more complex than this, so the formulas may not be exact but works for the most cases.
Notes
- Contrary to popular belief, life steal and spell vamp are not specific to physical and magic damage, respectively. Life steal will apply to anything classified as basic attack damage (including the magic damage from Takedown, Hextech Munitions and Infinite Duress), and spell vamp will apply to anything classified as ability damage (including the physical damage from Spear Shot and true damage from Reckless Swing).
See also
Template:Ability types