# Armor

1,936pages on
this wiki

Armor is a stat shared by all units, including minions, monsters, and buildings. Increasing armor reduces the physical damage the unit takes. Each champion begins with some armor which increases with level ( being the only exception). You can gain additional armor from abilities, items, masteries, and runes. Armor stacks additively.

Excluding whose base armor does not scale with levels, base armor ranges from 65.5 () to 96.7 ( and ) at level 18.

## Damage reduction

Incoming physical damage is multiplied by a factor based on the unit's armor:

$${\rm Damage\ multiplier}=\begin{cases} {100 \over 100+{\it Armor}}, & {\rm if\ }{\it Armor} \geq 0\\ 2 - {100 \over 100 - {\it Armor}}, & {\rm otherwise} \end{cases}$$

Examples:

• 25 armor → ×0.8 incoming physical damage (20% reduction, +25% effective health).
• 100 armor → ×0.5 incoming physical damage (50% reduction, +100% effective health).
• −25 armor → ×1.20 incoming physical damage (20% increase, −16.67% effective health).

## Stacking armor

Every point of armor requires a unit to take 1% more of its maximum health in physical damage to be killed. This is called effective health.

Example: A unit with 60 armor has 60% more of its maximum health in effective health, so if the unit has 1000 maximum health, it will take 1600 physical damage to kill it.

What this means: by definition, armor does not have diminishing returns in regard of effective hitpoints, because each point increases the unit's effective health against physical damage by 1% of its current actual health whether the unit has 10 armor or 1000 armor.

Note: Unlike health, increasing armor also makes healing more effective because it takes more effort to remove the unit's health than it does to restore it.

For a more detailed explanation, see this video.

When a unit's armor is negative because of armor reduction or debuffs, armor has increasing returns, because negative armor cannot reduce effective health to less than 50% of actual health. A unit with −100 has 66.67% (gains −33.33%) of its maximum health as effective health.

## Armor as Scaling

These use the champion's armor to increase the magnitude of the ability. It could involve total or bonus armor. By building armor items, you can receive more benefit and power from these abilities.

### Champions

• grants armor equal to 10% / 11.5% / 13% / 14.5% / 16% of his bonus armor to himself and the target ally (in addition to a base amount) for 3 seconds.
•  grants armor to himself equal to 20% of his bonus armor.
• grants armor to herself equal to 20% of her bonus armor (in addition to a base amount) for 3 seconds.
• grants armor to himself equal to 20 / 25 / 30 / 35 / 40% of his armor.
• deals magic damage equal to 30% of his armor (in addition to a base amount).
• deals magic damage equal to 10% of his armor (in addition to a base amount).
• grants attack damage to himself equal to 25% of his armor.
• grants his next basic attack bonus magic damage equal to 20% of his armor after using an ability.
• grants bonus armor to himself and nearby allied champions equal to 12% of his armor.
• active deals magic damage equal to 20% of his armor (in addition to a base amount) and reduces nearby enemy armor by 5% of his armor (in addition to a base amount) for 4 seconds.
• steals 20% of the target's armor. He continues to drain an additional 20% the target's armor over 4 second before decaying 4 seconds after the drain completes.

### Items

• active increases its slow duration by a base amount plus 0.5% of the wearer's total armor.

## Increasing armor

### Items

• : +40 armor. 750 gold.
• : +15 armor. 300 gold.
• : +100 armor, +400 mana. +20% cooldown reduction. Unique Aura: Nearby enemies suffer −15% attack speed. 2450 gold.
• : +20 armor, +250 mana. Unique Passive: +10% cooldown reduction. 950 gold.
• : +50 armor, +40 magic resistance. Unique Passive: Revives your champion upon death, restoring 30% of your maximum health and mana after 4 seconds of stasis (5 minute cooldown). 2750 gold.
• : +60 armor, +30 ability power, +500 mana, +10% cooldown reduction. Unique Passive – Spellblade: After using an ability, your next basic attack deals bonus physical damage equal to 125% of your base attack damage to surrounding enemies and creates a field for 2 seconds that slows enemies inside by 30% (1.5 second cooldown). 2900 gold.
• : +25 armor. Unique Passive – Blocks 10% of the damage from all basic attacks. Unique Passive – Enhanced Movement: +45 movement speed. 1000 gold.
• : +70 armor, +500 health. Unique Passive – Cold Steel: When hit by basic attacks, reduces the attacker's attack speed by 15% for 1 second. Unique Active: Slows the movement speed of nearby enemy units by 35% for 2 seconds (+ 0.5% armor) (+ 0.5% magic resistance) you have (60 second cooldown) (500 Range). 2850 gold.
• : +30 armor. Unique Passive - Killing a unit grants 0.5 bonus armor, and 0.5 bonus ability power. This bonus stacks up to 30 times. +25 ability power. 1200 gold.
• : +45 armor, +450 health. Unique Passive: Nearby enemies suffer 25 (+ champion's level) magic damage per second. 2600 gold.
• : +45 armor. Unique Passive – Cold Steel: When hit by basic attacks, reduces the attacker's attack speed by 15% for 1 second. 1050 gold.

#### Variable Availability

• TCH : +25 armor, +225 health, +250 mana, +20% cooldown reduction. Unique Passive – Trap Detection: Nearby stealthed enemy traps are revealed. Unique Active – Trap Detection: A stealth-detecting mist grants vision on the target area for 5 seconds, revealing enemy champions that enter for 3 seconds (60 second cooldown). 2130 gold.
• TC : +50 armor, +50 ability power, +50 magic resistance. Unique Passive – Tenacity: Reduces the duration of stuns, slows, taunts, fears, silences, blinds, and immobilizes by 35%. 2620 gold.
• S : +50 armor, +300 health, +100% health regen, +10% cooldown reduction. Unique Passive - Point Runner: Grants +30% bonus movement speed that build up over 2 seconds when near turrets. Unique Active: Prevents nearby enemy towers from attacking for 3 seconds (120 second cooldown). This effect cannot be used against the same tower more than once every 8 seconds. 2600 gold.
• S : 30 armor, +100% health regen. Unique Passive - Point Runner: Grants +30% bonus movement speed that build up over 2 seconds when near turrets. 1000 gold.
• SCH : +100 armor. Unique Passive: On being hit by basic attacks, returns 30% of damage, before any reductions such as armor, as magic damage. 2100 gold.
• TC : +45 armor, +100 ability power. Unique Passive: Increases ability power by 25%. Unique Active: Champion becomes invulnerable and untargetable for 2.5 seconds, but is unable to move, attack, cast spells, or use items during this time (90 second cooldown). 3540 gold.
• SH : +50 armor, +120 ability power. Unique Active - Stasis: Champion becomes invulnerable and untargetable for 2.5 seconds, but is unable to move, attack, cast spells, or use items during this time (90 second cooldown). 3300 gold.
• S : +50 armor, +50 magic resistance, +100% health regen. Unique Passive - Point Runner: Grants +30% bonus movement speed that builds up over 2 seconds when near turrets or Void Gates. Unique Active: Spawns a Void Gate at target location for 150 seconds. Every 4 seconds the gate creates a volatile that travels down the nearest lane, attacking enemy minions and exploding when attacking structures, but ignoring champions and void targets. 150 second cooldown. 2800 gold.

### Champion abilities

Note: Only the armor buff effect of these abilities is shown here, to read more information on each of these abilities, follow the link on each of them.

• allows her to enter an egg-state for up to 6 seconds upon reaching 0 health. While in this state, she will receive an armor modifier of −40 / −25 / −10 / +5 / +20.
• increases her armor by 20 / 30 / 40 / 50 / 60 for 5 seconds.
• increases armor by 15 / 17.5 / 20 / 22.5 / 25(+10% / 11.5% / 13% / 14.5% / 16% bonus armor) to himself and the target ally for 3 seconds.
• increases an allied champion's armor by 30 / 45 / 60 / 75 / 90 for 4 seconds.
• increases his armor by 2 × level when transform into .
• increases his armor by 20% of his bonus armor.
• increases his armor by 1 / 2 / 3 every second he remains in combat. This bonus stacks up to 10 times. Graves is considered in combat if he has dealt or received damage in the last 3 seconds.
• increases his armor by 5 / 15 / 25 / 35.
• increases his armor by 10 / 20 / 30 / 40 / 50 for 4 seconds.
• increases her armor by 20 / 30 / 40 / 50 / 60 (+ 20% bonus armor) for 3 seconds, deals damage after that time to units around her, and retains the defensive buff for an additional 3 seconds if any enemy is struck by the blast.
• increases his armor by 20 / 25 / 30 / 35 / 40% for 6 seconds.
• increases an allied unit's armor by 10 / 15 / 20 / 25 / 30 for 6 seconds.
•  passively increases his armor by 10 / 20 / 30.
• increases an allied champion's armor by 10 / 15 / 20 / 25 / 30 for as long as the ball is attached to them.
• increases her armor by 1.5 / 2 / 2.5 / 3 / 3.5 for 5 seconds upon attacking or being hit by an enemy, stacks up to 10 times. She can also activate this ability to gain max stacks.
• increases his armor by 40 / 60 / 80 / 100 / 120 for 6 seconds.
• Rengar lets out a battle roar, damaging enemies increases his armor by 10 / 15 / 20 / 25 / 30 for 4 seconds. Rengar gains additional 50% armor for each enemy champion or large monster hit.
• grants her 10 / 15 / 20 / 25 bonus armor each times she damages an enemy with an ability or attack for 2 seconds. Subsequent damage will increase the duration by 2 seconds up to a cap of 8 seconds, after where damage will refresh the duration.
• passively increases her armor by 5 / 10 / 15 / 20. This bonus is doubled while she is in Dragon Form.
• increases his armor by 35 / 50 / 65 for 25 seconds.
• passively increases his armor by 10 / 15 / 20 / 25 / 30 while the ability is not on cooldown and grants himself and nearby allied units' 12% of his armor.
• passively generates souls for him to collect, with each soul collected granting 0.75 armor permanently.
• takes 40% of the target's armor and gains an equal amount of armor. Over 4 seconds, the bonus armor is doubled. The armor bonus lasts for another 4 seconds after the drain completes.
• increases his armor by 60 / 90 / 120 for 5 seconds upon activation.
• passively grants him 4 / 6 / 8 armor for each nearby enemy champion.
• increases his armor by 15 / 20 / 25 for each enemy champion hit for 8 seconds.

### Masteries

• increases bonus armor and magic resistance by 2.5 / 5%.
• increases your champion's armor by 2 / 3.5 / 5.
• grants your champion 1 / 2 / 3 / 4 armor and 0.5 / 1 / 1.5 / 2 magic resistance for each nearby enemy champion

### Runes

• Armor runes increase armor.

## Ways to reduce armor

See armor penetration. Note that armor penetration and armor reduction are different.

## Armor vs. Health

Note: The following information also applies to Magic Resist.

It can be helpful to understand the equilibrium between maximum HP and Armor, which is represented in the graph[1] on the right. The equilibrium line represents the point at which your champion will have the highest Effective Health against that damage type, while the smaller lines represent the baseline progression for each kind of champion from level 1-18 without items. The most important point to keep in mind when studying this graph is the fact that HP is much easier to come by in a full item build, therefore you should not worry about trying to hit the exact equilibrium. You can also see that for a somewhat brief period in the early game HP is the most gold efficient purchase.

There are many other factors which can effect whether you should buy more Armor or HP, such as these key examples:

• Whether or not the enemy is capable of delivering true damage or percent health damage, thus reducing the value of HP stacking.
• The presence of resist or HP steroids built into your champion's kit, such as in Garen's or Cho'Gath's .
• Against sustained damage Life steal and healing abilities can be considered as contributing to your maximum HP (while being mostly irrelevant against burst damage).
• The need to prioritize specific items mainly for their other qualities (regardless of whether or not they contribute towards the ideal balance between HP and resists).

## Trivia

A level 18 with 6 , 3 points in , 2 points in , 4 points in , , ,  aura, Glyphs and Marks of Armor, Seals and Quintessences of Scaling Armor, and enabled will give a total of approximately 1643 armor.

Having an enemy with the same setup use on  will yield a total of roughly 1789 armor. This is the highest possible finite amount of armor (without using metagame effects—see below), and reduces physical damage by 94.7%.

It is still possible to go higher through metagame functions. If a summoner disconnects from the server and is in the fountain, his champion will gain 1000 armor. With the same setup as above, a disconnected  with a disconnected  will have approximately 2779 armor.  cannot exceed this. This reduces physical damage by 96.5%.

If disconnecting grants armor quickly enough that  remains active, can reach 3143 armor. This reduces physical damage by 96.9%.

, with his effectively infinite stacking, can obtain a maximum of 749999.25 armor off his passive alone. With the same set-up as above, he can obtain a total of about 788575 armor, reducing physical damage by 99.9873205%. If he disconnects, he can obtain up to 789626 armor, reducing it by 99.987337%

## References

1. Should you buy Armor or Health?