Magic resistance

Magic resistance (or MR) is a stat that all units have, including minions, monsters, and buildings. Increasing magic resistance reduces the magic damage the unit takes. Each champion begins with some magic resistance which may increase with level. You can gain additional magic resistance from abilities, items, masteries, and runes. Magic resistance stacks additively.

All champions begin with. Currently no ranged champion gains magic resistance per level, but most melee champions do except  and.

,, ,  and  do not gain magic resistance per level because they are not always melee champions due to their variable attack range.

All champions that do gain magic resistance per level gain magic resistance per level, reaching  at level 18.

Damage reduction
Magic Resistance reduces the damage of incoming magical attacks by a percentage. This percentage is determined by the formula: Damage Reduction = Total Magic Resistance / (100 + Total Magic Resistance). For example, a champion with 150 points of magic resistance would receive 60% reduced damage from magical attacks. Incoming magic damage is multiplied by a factor based on the unit's magic resistance(same with armor):

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

Examples:
 * 25 magic resistance &rarr; &times; incoming magic damage (20% reduction).
 * 100 magic resistance &rarr; &times; incoming magic damage (50% reduction).
 * &minus;25 magic resistance &rarr; &times; incoming magic damage (20% increase).

Stacking magic resistance
Every point of magic resistance requires a unit to take 1% more of its maximum health in magic damage to be killed. This is called "effective health."
 * Example: A unit with 60 magic resistance has 160% of its maximum health in its effective health, so if the unit has 1000 maximum health, it will take 1600 magic damage to kill it.

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

For a more detailed explanation, see this video.


 * Unlike health, increasing magic resistance makes healings and shields more effective because it requires more effort from your enemies to remove the bonus health granted. This is called indirect scaling.

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

Champions

 * grants magic resistance equal to to himself and the target ally (in addition to a base amount) for 3 seconds.
 * grants him bonus ability power equal to.
 * grants additional magic resist equal to +  for its duration.
 * takes and gains an equal amount of magic resistance. Half of this magic resistance is stolen on cast, and the next half is taken over 4 seconds. The magic resistance bonus/reduction lasts for another 4 seconds after the drain completes.

Champion abilities
Note: Only the magic resist 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 taking lethal damage. While in this state, she will receive a magic resistance modifier of.
 * increases her magic resistance by for 5 seconds.
 * increases magic resistance by +  to himself and the target ally for 3 seconds.
 * increases an allied champion's magic resistance by for 4 seconds.
 * increases his magic resistance by (2Gnar's level) when transformed into.
 * permanently gains bonus magic resistance every time he kills an enemy, up to a maximum of 30.
 * increases his magic resistance by for 4 seconds stacking up to 4 times when shooting pellet, up to  bonus magic resistance.
 * increases his magic resistance by +  for 8 seconds.
 * increases his magic resistance by for 4 seconds.
 * increases his magic resistance by.
 * increases her magic resistance by +  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.
 * passively increases his magic resistance by . He loses the passive while his ability is active.
 * increases an allied champion's magic resistance by as long as the ball is attached to it.
 * increases her magic resistance by 12% doubled to 24% while below.
 * increases his magic resistance by for 6 seconds.
 * lets out a battle roar, damaging enemies increases his magic resist by for each enemy champion or large monster hit for 4 seconds.
 * passively increases her magic resistance by . This bonus is doubled while she is in dragon form.
 * increases his magic resistance by for 25 seconds.
 * immediately steals, and a further 20% over 4 seconds. These magic resistance bonuses lasts for another 4 seconds after the drain completes.
 * increases his magic resistance by for 5 seconds.
 * grants him magic resistance for each visible nearby enemy champion.
 * increases his magic resistance by for each enemy champion hit for 8 seconds.

Masteries

 * increases and  by %.
 * grants magic resistance and armor for each nearby enemy champion.

Other

 * Disconnecting gives approximately +1000 magic resistance after a delay.

Ways to reduce magic resistance
See magic penetration. Note that magic penetration and magic resistance reduction are different.

List of champions' magic resistance

 * 63 champions have from level 1 to level 18. These champions are mostly ranged champions, with the exception of, and.
 * 65 champions start with at level one, and at  at level 18. These champion are all melee champions, without exception.

Trivia
[Last updated 05/01/2015 on patch 5.24] must:
 * One of the biggest amount of magic resistance any champion can obtain is  (which reduces by %), being a level 18.
 * Have all magic resistance runes and masteries
 * 9 Scaling Marks of Magic Resistance
 * 9 Scaling Seals of Magic Resistance
 * 9 Scaling Glyphs of Magic Resistance
 * 3 Scaling Quintessences of Magic Resistance
 * 5 points in
 * 5 points in
 * Have 6 or  or any combinaison of both
 * Be close to an allied champion equiped with a or a
 * cast by a
 * can only use on one target :
 * cast by an.
 * can only use on one target :
 * cast by a with the maximum amount of bonus magic resistance
 * can only use on one target :.
 * (rank 3) cast on 5 enemy champions


 * Relevant mathematics:


 * Bonus Magic Resist (before )
 * Magic Resist(())

Having an enemy with the same setup use  on  will yield a total of  magic resistance. This may be the highest possible finite amount of magic resistance (without using metagame effects—see below), and reduces magic damage by %.

Relevant mathematics:


 * Magic Resist
 * Magic Resist(())

It is still possible to go higher through metagame functions. If a summoner disconnects from the server and is in the fountain, his/her champion will gain 1000 magic resistance. With the same setup as above, a disconnected will have approximately  magic resist. cannot exceed this. This reduces magical damage by %.


 * Prior to Patch 3.10, a level 18  with 1, 5 , 3 points in , 3 points in , , , , , an allied  aura, a full page of  runes, and  active gave a total of approximately 1004 magic resist. Switching  for  and having an enemy  with the same setup use  on  and the allied  use  on the enemy , yielded a total of approximately 1297 magic resist. This is the highest possible amount of magic resistance, which is reduction.
 * If disconnects from the fountain and has the same setup, he will have 2108 magic resist. This is a  reduction.
 * NOTE: This calculation does not include the mastery.

Magic resistance Magieresistenz Resistencia mágica Résistance magique Odporność na magię Магическое сопротивление 魔法抗性