Skip to content

LoL Armor/Magic Penetration: Part I: Introduction

January 20, 2011

Penetration and You.

Today, a friend asked me to explain to him how armor and magic penetration work, and a blog post seems the perfect way to do it! In the current state of the meta-game at level 30, team composition seems to be moving away from the traditional glass-cannon DPS champions defended by untouchable tanks toward more evenly distributed damage and toughness across the whole team (carry Ashe with Banshee’s Veil, tank Garen with Hexdrinker and Sunfire Cape, Rod of Ages on almost every AP carry?). To counter these tanky teams, a player needs to understand the role that armor and magic penetration play in their ability to deal damage.

Two types of penetration

(note, armor and magic penetration work the same)


Flat Penetration: Flat penetration reduces the effective amount of damage resistance your target has against your physical or magic damage. If  penetration is displayed on an item, rune, or mastery without a percent sign, you can assume the amount is flat penetration. If you have X magic penetration and your target has Y magic resist, your magic abilities will do damage to that target as if they had Y-X magic resist instead.

Percent Penetration: Percent penetration reduces your target’s effective armor or magic resist by a percent of their total Armor/MR AFTER your flat penetration is applied. This kind of penetration is always denoted by a %. If you have X flat armor penetration and Y percent armor penetration, and your target has Z armor, your physical attacks do damage as if your target only had (Z-X) * Y% armor.

Sources of penetration


Flat Magic Penetration: (runes) Greater Marks of Insight, Greater Quintessences of Insight, (items) Haunting Guise, Sorcerer’s Shoes, Malady.

Percent Magic Penetration: (items) Void Staff, (masteries) Archaic Knowledge.

Flat Armor Penetration: (runes) Greater Marks of Desolation, Greater Quintessences of Desolation, (items) Black  Cleaver, Brutalizer, Youmuu’s Ghostblade, Stark’s Fervor, Sword of the Divine, (masteries) Sunder.

Percent Armor Penetration: (items) Last Whisper


From → Games

One Comment
  1. mappum permalink

    Two kinds of penetration? That’s called double penetration.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: