Magic penetration in the League of Legends

Magic penetration is calculated using exactly the same formulas, but a little simpler, since there is no lethality here, but only a percentage and quantitative reduction in magical resistance.

The most important thing to remember is that the reduction in magical resistance goes strictly according to the list:


Quantitative reduction in resistance

Percentage Resistance Reduction

Quantitative resistance penetration

Percentage resistance penetration

Magic resistance reduction can leave the enemy not only with 0 defense, but also bring the resistance indicator to negative values. Magic penetration can only reduce resistance to 0.

Magic penetration in the League of Legends

In order to more clearly outline the mechanics of resistance reduction, let’s imagine this situation: your champion has 20 magic resistance reduction and 30% magic resistance reduction. In addition, the target is under the effect of 10 magic penetration penetration and 40% magic penetration. That is, we take into account all four factors of resistance reduction. As an example, let the enemy have 80 units of magic resistance and let’s see how much damage the enemy should receive:


80 will first be reduced to 60 due to 20 magic resistance reduction

Next 60 will be reduced to 42 due to 30% magic resistance reduction

Then 42 will turn into 27.3 thanks to 35% magic resistance penetration

And finally the number 27.3 will come to the final value 17.3 due to 10 magic resistance penetration

That is, out of 80 resistance, the enemy will only have 17.3 left.


If, with the same values of magic reduction and magic penetration, we attack an enemy with 18 units of resistance, then the calculation formula will be much simpler. The fact is that already at the first stage of calculations, the value of 20 will be subtracted from 18 resistance and the enemy will have -2 resistance. All subsequent calculations will stop and in fact our champion’s skills will deal full magic damage.