Did you know a champion with -15 armor takes more damage than one with 0 armor? This shows how complex armor mechanics are in League of Legends. Knowing how armor and penetration work is key to being effective on the Rift.
Armor in League of Legends is a vital defense against physical damage in League of Legends. It’s a part of what makes champions strong. Whether you’re a tank or a carry, understanding armor is important.

League of Legends armor stats are more than just numbers. They interact with items, abilities, and champion levels. This guide will show you how armor value affects gameplay and how to build your champions.
This guide covers everything from damage reduction to armor penetration. You’ll learn how to use armor to your advantage. You’ll also find out how to build or counter armor-heavy teams.
Table of Contents
Key Takeaways
- Negative armor values result in increased damage taken
- Armor effectiveness varies based on total armor and enemy penetration
- Lethality provides flat armor penetration at all levels
- Percentage armor reduction is more impactful against high-armor targets
- Understanding armor mechanics is key for optimal builds and champion selection
Understanding Armor Mechanics in League of Legends
Armor is very important in League of Legends. It helps your champion defend against physical damage. Let’s explore how armor works and its impact on your gameplay.
Base Armor vs Bonus Armor
In League of Legends, there are two types of armor: base and bonus. Base armor increases as your champion levels up. Bonus armor comes from items, runes, and abilities. Knowing the difference is essential for a strong defense.
How Armor Reduces Physical Damage
Armor helps reduce physical damage you take. Each armor point boosts your effective health by 1%. This makes your champion harder to defeat.
Armor | Damage Reduction | Effective Health Increase |
---|---|---|
25 | 20% | 25% |
100 | 50% | 100% |
200 | 66.6% | 200% |
Armor is a defensive stat that reduces incoming physical damage. When a champion takes physical damage, their armor reduces that damage before it affects their health pool. Here’s how it works:
Basic Concept:
- Armor converts incoming physical damage (pre-mitigation) into a lower amount (post-mitigation)
- The higher your armor, the more physical damage you can absorb
- Each point of armor effectively increases your health by 1% against physical damage
Damage Calculation:
For positive armor values (which is most common), the formula is:
Post-mitigation damage = Physical damage × (100 / (100 + Armor))
For example:
- If you have 100 armor and take 1000 physical damage
- The actual damage you receive would be: 1000 × (100 / (100 + 100)) = 500 damage
Effective Health:
You can think of armor as a way to make your health pool more effective against physical damage. For instance:
- A champion with 1000 health and 100 armor
- Has an effective health pool of 2000 against physical damage
- Because each point of armor adds 1% to your effective health
This makes armor particularly valuable when combined with high health totals, as they multiply each other’s effectiveness.
Examples using 1000 health and 1000 pre-mitigation damage, for the sake of simplicity:
- 25 Armor
- 25% effective health increase → 1000 nominal health becomes 1000 × (1 + 25 ÷ 100) = 1000 × 1.25 = 1250 total effective health against physical damage
- 1000 raw damage ÷ (1 + 25 ÷ 100) = 1000 ÷ 1.25 = 800 post-mitigation damage → 20% total physical damage reduction
- 100 Armor
- 100% effective health increase → 1000 nominal health becomes 1000 × (1 + 100 ÷ 100) = 1000 × 2 = 2000 total effective health against physical damage
- 1000 raw damage ÷ (1 + 100 ÷ 100) = 1000 ÷ 2 = 500 post-mitigation damage → 50% total physical damage reduction
- 200 Armor
- 200% effective health increase → 1000 nominal health becomes 1000 × (1 + 200 ÷ 100) = 1000 × 3 = 3000 total effective health against physical damage
- 1000 raw damage ÷ (1 + 200 ÷ 100) = 1000 ÷ 3 = 333.3 post-mitigation damage → 66.6% total physical damage reduction
Armor Scaling and Effectiveness
Armor increases your effective health linearly. For example, 100 armor doubles your health against physical damage. This makes stacking armor a strong strategy for tank champions.

Getting the right mix of armor and health is vital in League of Legends. Mastering armor mechanics will help you make smarter choices in your gameplay and itemization.
Armor Penetration and Reduction Systems
League of Legends armor penetration systems are complex but key for better damage. Knowing these mechanics can boost your gameplay and strategy.
Flat Armor Penetration and Lethality
Flat armor penetration cuts a target’s armor by a set amount. Lethality, its advanced form, grows with your champion’s level. At level 18, 18 lethality means 18 flat armor penetration. It’s great against weak targets with little armor.
Percentage Armor Penetration
Percentage armor penetration takes a part of the target’s armor. For example, Lord Dominik’s Regards gives 35% armor penetration. This is super useful against heavily armored foes.
Armor Reduction Effects
Armor reduction is different from penetration. It lowers the target’s actual armor. This can be done through abilities or items and can even make armor go below zero, increasing physical damage.
Order of Calculations
The game follows a specific order for applying armor penetration and reduction:
- Flat armor reduction
- Percentage armor reduction
- Percentage armor penetration
- Flat armor penetration (Lethality)
Knowing this order is key for a good build strategy. Mixing percentage and flat penetration can be very effective against both tanky and squishy opponents.
Item | Attack Damage | Armor Penetration |
---|---|---|
![]() | 60 | 18 Lethality |
![]() | 55 | 18 Lethality |
![]() | 55 | 12 Lethality |
![]() | 40 | 35% Armor Penetration |
Don’t forget, armor penetration runes can also boost your damage. Try out different setups to find what works best for you and your champion.
Armor in League of Legends: Items and Build Strategies
Building armor in League of Legends can change the game. The right armor items can shift the battle’s outcome, helping tanks and frontliners. Let’s explore some key armor choices and when to use them.
Core Armor Items
Dead Man’s Plate is great for champions who need to close gaps quickly. It has 50 armor and 300 health, perfect for initiators.
Frozen Heart, with 100 armor, is ideal against enemies that rely on attack speed.
Randuin’s Omen is the best choice against crit-heavy teams. It has 70 armor and a unique passive.

Situational Armor Choices
Thornmail is the top pick against teams that rely on healing. It offers 75 armor and reduces healing.
Sunfire Cape, with 40 armor and AOE damage, is perfect for tanks who want to deal damage while taking hits.
When to Prioritize Armor vs Health
Deciding between armor and health depends on the enemy team. Against physical damage dealers, go for armor. For mixed damage, balance both. Early game, health is more efficient, but armor becomes more valuable later.
Item | Armor | Health | Cost | Best For |
---|---|---|---|---|
![]() | 50 | 300 | 2900 | Initiators |
![]() | 100 | 0 | 2700 | vs Attack Speed |
![]() | 70 | 300 | 3000 | vs Crit |
![]() | 75 | 0 | 2700 | vs Healing |
![]() | 40 | 300 | 2750 | AoE Damage |
Investing in armor is best when you already have good health. For damage dealers, a mix of offense and defense is often better than just armor.
How Armor Stacking Works
Armor stacking is a straightforward but powerful mechanic. Each point of armor increases your effective health against physical damage by 1%. This creates a linear scaling that never diminishes in value.
The Formula:
Effective Health = (1 + Armor/100) × Base Health
Simple Example:
- Champion has 1000 base health and 60 armor
- Effective health = (1 + 60/100) × 1000
- Effective health = 1.6 × 1000 = 1600
This means enemies need to deal 1600 physical damage to defeat this champion, even though they only have 1000 health.
Key Points:
- Each armor point consistently adds 1% effective health
- There are no diminishing returns
- The value of armor remains constant regardless of how much you already have
Special Case – Negative Armor:
- Negative armor works differently
- Cannot reduce effective health below 50% of base health
- Example: -100 armor results in 66.67% effective health
- This is rare and usually only happens with specific debuffs
This makes armor a reliable defensive stat that scales well throughout the game, especially when combined with health items.

Optimal Balance Between Armor and Health
The ideal balance between armor and health follows these formulas:
- For Armor:
Health = 7.5 × (armor + 100)
- For Magic Resistance:
Health = 6.75 × (magic resistance + 100)
When to Buy What
Early Game:
- Health is typically more gold-efficient early
- This assumes you’re facing primarily one damage type
- If enemies have mixed damage (physical and magical), health becomes even more valuable
Key Factors to Consider:
- Healing Efficiency
- More armor makes healing more effective
- Each point of health healed becomes more valuable with higher resistances
- Damage Types
- Health helps against all damage types
- Consider enemy team composition:
- Mixed damage → Favor health
- Burst damage → Health can be better
- True damage → Favor health (armor doesn’t help)
- Percent health damage → Favor resistances
- Champion-Specific Factors
- Built-in defensive abilities (like Leona’s Eclipse)
- Health-scaling abilities (like Cho’Gath’s Feast)
- Healing or shield abilities in your kit
- Enemy Team Composition
- Armor penetration items → Might favor health
- Sustained damage → Consider healing/vampirism
- Burst damage → Raw health pool matters more
- Item Priorities
- Sometimes you need specific items for their unique effects
- These might not follow the optimal health/armor ratio but are still necessary
Remember that this is a general guide, and specific game situations might require different approaches to defensive itemization.
Champion Abilities and Armor Interactions
In League of Legends, champions’ abilities can change how armor works. These changes can greatly affect how you play, both offensively and defensively. Let’s look at some examples of how champions can alter armor values.
Darius, the Hand of Noxus, has a special ability called Apprehend. It gives him up to 25% bonus armor penetration. This lets him break through enemy defenses easily.
Yasuo‘s Last Breath, on the other hand, gives him 50% armor penetration against bonus armor. This makes him very dangerous to tanky opponents.
Some champions can reduce the armor of enemies nearby. Trundle‘s ultimate ability can take armor from a target, making him stronger.
Rengar‘s Empowered Battle Roar also lowers the armor of enemies around him, setting up powerful combos.
A list of champions whose abilities interact with armor includes:
Malphite: Gains bonus armor from his passive
Rammus: Transforms armor into attack damage
Leona: Increases her armor and magic resist with Eclipse
Taric: Grants bonus armor to himself and allies
Understanding these armor interactions is key to using your champion’s abilities to the fullest. Whether you want to break through enemy defenses or strengthen your own, knowing how abilities affect armor can give you a big advantage on the Rift.
Conclusion
Understanding armor in League of Legends is key to mastering defense and countering enemies. Armor scaling is important, with base armor at level 18 ranging from 87 for Kassadin to 149.4 for Mega Gnar. Each armor point boosts your health by 1%, making it vital for staying alive.
Armor penetration is essential for offense. Items like Thornmail, costing 2450 gold, offer strong defense. Remember, armor’s effect drops off after 200 points. Each point after that reduces damage by less than 1%, so balance is important.
Knowing these armor mechanics helps you make better choices in champion select and itemization. Whether you’re taking damage, boosting carry, or supporting your team, this knowledge improves your game. Stay updated on League of Legends’ armor system to excel in your matches.
FAQ
What is armor in League of Legends?
Armor in League of Legends is a defensive stat that reduces incoming physical damage. Every champion has a certain amount of base armor, which increases with level. Bonus armor can be obtained through items, runes, and abilities. Armor increases the effective health of a champion against physical damage, making them more durable in combat.
How does armor reduce physical damage?
Armor reduces physical damage through a formula that calculates damage reduction. The formula is: Damage reduction = Armor / (100 + Armor). For example, 100 armor provides 50% damage reduction, meaning a champion with 100 armor takes only half the physical damage they would normally receive. This calculation applies to all sources of physical damage, including auto-attacks and physical abilities.
What is the difference between base armor and bonus armor?
Base armor is the innate armor a champion has without any items or runes. It increases naturally as the champion levels up. Bonus armor is any additional armor gained from items, runes, or abilities. Some abilities and items specifically interact with base armor or bonus armor, making the distinction important for certain champion interactions and item choices.
How does armor penetration work in League of Legends?
Armor penetration lets champions bypass some of their target’s armor. There are two types: flat penetration (now called Lethality) and percentage penetration. Flat penetration is better against low-armor targets, while percentage penetration works against heavily armored foes.
What is Lethality and how does it differ from flat armor penetration?
Lethality is a stat that converts into flat armor penetration. It’s designed to be balanced throughout the game, unlike the old flat armor penetration system.
How does armor scaling work in League of Legends?
Armor scaling shows how well armor reduces damage as you get more. Each armor point increases your health against physical damage. But, the damage reduction per point decreases as you stack more armor.
When should I prioritize building armor over health?
Prioritize armor against physical damage threats. But, a mix of health and armor is best. Health works against all damage types, and some effects damage based on max health.
How do champion abilities interact with armor?
Some champions have abilities that give bonus armor, reduce enemy armor, or provide armor penetration. Knowing these interactions helps maximize your champion’s effectiveness and counter enemy strategies.
What are some effective ways to counter armor stacking in League of Legends?
To counter armor stacking, build items with percentage armor penetration. Use champions with armor reduction abilities. Or, focus on magic damage, which armor doesn’t mitigate.
How does armor affect my effective health in League of Legends?
Armor boosts your effective health against physical damage. Each armor point increases your health pool against physical damage by 1%. This makes you harder to take down with physical attacks.