Kayle SilverSkin

Kayle shreds everything!

Hiya reader! While having a fun discussion with the always fun and lovely Interceptor402 (who can always be found hanging around the awesome and divined KayleSquare Kayle page because Kayle is always super awesome!) a thought occurred to crunch the numbers oh how effective the reduction/penetration flip.

So this here is the purpose of this blog: "How much did the reduction/penetration flip increase your champion's damage?"


ClariS Inactive

The time taken crunching the numbers: 25 minutes

First, I will only reference armor throughout this entire blog, but all the findings here holds true for magic resistance. Second, we need a very quick overview on this order so people in the dark can understand what I'm talking about.

In Season 3, the order of reduction and penetration is:

  1. Flat magic reduction
  2. Percent magic reduction
  3. Percent magic penetration
  4. Flat magic penetration

Before season 3, the order was:

  1. Percent magic reduction
  2. Flat magic reduction
  3. Flat magic penetration
  4. Percent magic penetration


Ryze ProfessorLoading

For science!!

Now what can we get out from these data. By the data, we actually get a very very simple equation we can use to discover the difference in armor. This equation holds true for all different possible values (I have tested it countless times) and the equation is:

Difference in armor = (value of Last Whisper item % Pen)  × (value of The Brutalizer item flat Pen  ÷ 100)

See how simple math is :)

By studying the equation, you can quickly learn something. You only start seeing a noticeable difference when you stack % armor penetration. And this is where the truth lies.

There is only three sources to grab % armor penetration
Same for % magic penetration


The Reduction/Pen flip is only a noticeable difference if you grab Last Whisper item Last Whisper or you're DariusSquare Darius. If your champions falls under one of these two options, then you see an average increase of 3 - 10% (target has 60 - 175 armor) due to the flip.

With that, it is a rather good change, but... if you do not have Last Whisper item Last Whisper or you're not DariusSquare Darius, then at best, you see an increase of 1.5%. Beyond that, everything else is really unnoticeable.

Some other information

You didn't even mention about reduction?

  • Reduction got nerf due to the flip (% now comes after flat), and the order of reductions to penetration did not change, so the two does not affect effect each other, therefore there is no change.
    • Second, it's hard to find overlap as the only possible way to get flat armor reduction and % armor reduction is through champions abilities. In either case, to calculate the lost, use the same equation I provided.

Who were the champion actually benefited from the flip?

  • Not including any outside factors besides the reduction/pen flip, the champions are DariusSquare Darius, OlafSquare Olaf, and XerathSquare Xerath because they are the only champions that have penetration within their kit. All other champions have reduction and at best, they have a 0% increase.
  • In addition, basically champions that would desire Last Whisper item Last Whisper or Void Staff item Void Staff.
    • Basically anything that provides % penetration benefited the most out from this change, and then those with flat penetration gains a little. Anything with reduction (at worst) has been nerfed, but due to the small amount of sources where flat armor reduction appear, it's rarely a nerf.

Did The Black Cleaver item The Black Cleaver become overpowered because of this flip?

  • No. Black Clever would had been overpowered as well in season 2 if it was released with the 30% armor reduction and 15 flat armor pen. The order of which these appears are the same, and has a very tiny difference regardless of the order.

Final Thoughts

Claris Kitty's Belly

Your next assignment is to hug a cat

No not take this information wrongly. This flip has been a buff overall, but the buff is only noticeable is if your champion stacked resistance penetration (like grabbing The Black Cleaver item The Black Cleaver or Liandry's Torment item Liandry's Torment) and grab Last Whisper item Last Whisper or Void Staff item Void Staff. Outside of that, the buff is very marginal. It's a buff, but a tiny one.

I hope this blog has been really helpful for you and taught you something completely new. If you have any questions, please feel free to ask and I'll answer. Thank you for your time.