Lethality vs. Armor Penetration

The big debate that has been going on the past few months is about the balance of Lethality. Itemizing against enemy team compositions is always tricky and determining whether to build Lethality or Armor Penetration is always up for discussion. First, we need to look at the difference between the two and then we will be able to determine which is more useful in what situation.

Armor Penetration is pretty simple to understand. It reduces the effectiveness of enemy champions Armor by a percentage. Simply, if you have 10% Armor Penetration and the enemy has 100 Armor, it would be as if the enemy champion only had 90 Armor instead of 100. Pretty simple to understand. Lethality is bit different. Lethality gives flat Armor Penetration instead of percentage Penetration with the formula = Lethality x (0.6 + 0.4 × level ÷ 18). Basically, if you buy Duskblade of Draktharr you will not receive the full 18 Lethality until you reach level 18. To calculate how much Lethality it will give you, just substitute your level into the formula, for example if you were level 12 with Duskblade of Draktharr: 18 x (0.6 + 0.4 × 12 ÷ 18) = 15.6 flat Armor Penetration. Now that we know the difference between Lethality and Armor Penetration, let’s look at some scenarios on when to build each.

Let’s pretend we are in a scenario playing an AD assassin mid lane such as Zed or Talon. Your job as an assassin is to kill enemy champions that are out of position, get picks for your team, and kill the enemy carries before they can do anything in a fight. Let’s look at some typical runes for an ADC to see how Lethality will compare:

The average base Armor stats for all marksman champions at level 1 is 22.74 while the average base Armor at level 18 is 80.48. Assuming they do not build any defensive items until a late game Guardian Angel with 30 Armor they are typically sitting around 31.74 – 89.48 Armor with the extra 9 Armor that 9 Armor Seals give. If you were to build all three Lethality items (Duskblade of Draktharr, Edge of Night, and Youmuu’s Ghostblade) which have 18 Lethality, you will essentially have 54 flat Armor Penetration at level 18. With the average Armor of marksman champions at level 18 being 89.48 with Armor Seals and you having 54 flat Armor Penetration for Lethality, it will be as if the enemy ADC only has 35.48 Armor, decreasing your physical damage done to them by roughly 27%. If you were to build an Armor Penetration item such as Mortal Reminder or Lord Dominik’s Regards which has 35% Armor Penetration, at level 18 the enemy ADC would have its 89.48 Armor reduced to 58.2, which would decrease your AD damage done to them to them by 36% instead of the 27% with Lethality. So, in cases where you are trying to assassinate an enemy ADC as an AD assassin mid such as Zed or Talon, building Lethality is the preferred choice. Now, if Lethality seems so good against enemy carries why would you ever build Armor Penetration items?

One thing you need to look at is the type of champion you are playing and what their kit revolves around. For AD assassins, they rely on getting to backline focusing squishy champions and using their full combo to burst down an enemy carry. Their spells and combos usually have long cooldowns that you cannot spam which makes it hard for them to kill off tanks. They are also typically melee champions meaning that if they do not get their full combo off they must rely on auto-attacking to finish the job. AD Carries on the other hand rely a lot more on auto attacks as opposed to full bursts and do not have the kit to dive backlines to kill enemy champions. They focus on the closest target in a team fight (which is usually a frontline tank) until another priority target becomes available. This keeps them safe while still outputting as much damage as possible. Since they are primarily focusing on the frontline tanks, lets calculate which set of items between Lethality and Armor Penetration will work better in their situation.

For this example, let’s pretend we are playing as an ADC. While during a team fight we need to focus down the tanks until we can reach their backline to kill off the carries. If they are running a frontline tank such as Maokai or Nautilus, they will typically have 2-3 Armor items depending on if your team is more AP or AD heavy. Let’s say on average a frontline tank will have anywhere between 200-300 Armor and you want to know whether Lethality is still good or if you should build Armor Penetration. If we build all three Lethality items, we will have 54 flat Armor Penetration at level 18. This means that they will have anywhere between 146-246 effective Armor, decreasing our damage done to them anywhere between 61% and 73%. If we were to build an Armor Penetration item with 35% Armor Penetration, it would reduce their effective armor down to between 130-195 which only reduces our damage done to them between 56% and 65%. So, in cases where we are auto-attacking at a constant rate against frontline tanks, percent Armor Penetration is better to build than Lethality.

Here we can see C9 Sneaky positioning in his backline while fighting the enemy teams front line tank:

If you watch LCS or other competitive League scenes, you’ll notice that their builds and picks are slightly different than those built in solo queue. There is a reason you rarely see Duskblade of Draktharr in high elo and competitive play and it is not because Lethality is not good. One reason is the current meta. Currently, hypercarry ADCs and top carry champions are being prioritized while control mages are being prioritized in the mid lane. AD assassins are very low on the tier list with champions such as Zed, Talon, and Rengar seeing little play time. This is because AD carries such as Jarvan IV, Fiora, and Renekton are seeing more play in the top lane as opposed to AP carries or tanks such as Rumble, Maokai, and Shen. Since all these carry top lane champions are primarily AD, having a third AD champ in the mid lane to go along with the ADC role would not be beneficial as the enemy team could stack Armor against it. If a team is going to run an AD assassin in the mid lane there will typically be an AP or tank top and jungle. This just goes for the competitive scene and everyone knows that no one in solo queue primarily follows the meta.

In conclusion, it is usually better to build Lethality on assassin champions that have burst abilities in their kits that prioritize enemy squishy champions and ADCs, while it’s probably better to build percent Armor Penetration on AD champions that are outputting a constant stream of damage to enemies with higher amounts of Armor such as ADCs against frontline tanks. While neither are bad to build against enemies with Armor, the main thing you need to focus on is what kind of playstyle are you looking to achieve. Are you playing a more passive poke composition or a pick comp? While there are many factors to go into building items hopefully you now know a little more on the effects of Lethality vs. Armor Penetration.

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