The Effect of Season 3 Penetration Rune Changes on AD Carries

The Effect of Season 3 Penetration Rune Changes on AD Carries

Before we start today's blog, I'd like to give a shoutout to Forneas for redesigning my blog's images yet again with the new header image you see above as well as a fun new reddit icon; you can find more of his work at  But more importantly, today we are bringing to you new calculations on the effect of attack damage runes versus armor penetration on the latest Season 3 patch.  The most recent patch marks a change in how magic and armor penetration is calculated: flat penetration is now calculated after percent penetration has been factored in instead of the other way around, and flat penetration runes has been nerfed to reflect this change as seen below.

In today's calculations, we're going to use a few basic assumptions about damage calculations.  All basic attacks will be performed by a Graves (so we are using his base damage and AD scaling) that has invested fully into the offensive mastery tree, the relevant masteries being Deadliness (12 AD @ level 18), Weapon Expertise (8% armor penetration), Havoc (2% more damage dealt), Brute Force (+3 AD), and Sunder (5 armor penetration).  Since this post is meant for AD carries in general instead of just Graves, we will be ignoring damage from skills (Q and R).  Additionally, we are assuming that the target dummy does not have any armor or damage modifiers that are commonly found in the defensive tree.  Damage calculated is using normal autoattacks (no critical hits) without any attack/defense modifiers. Runes used for the simulation assume either 15 attack damage or 19.5 armor penetration.

The early game: level 1

During Season 2, there was a small armor range (30 to 60ish armor) where armor penetration was actually stronger than attack damage runes at around 75 damage.  With the changes to the new penetration system, there is no point where armor penetration is superior to bonus attack damage during the early game; however, the difference isn't dramatic enough that you will be outclassed against another AD carry if you own different runes: assuming a generic starting armor value of 30 (at level 1, the range of champion armors can range from about 20 for supports to 35 for bruisers), a champion like Graves should see a difference of about 3 damage per autoattack landed on an enemy champion, or about 5% more damage dealt overall.  Expand the spoiler below to see the difference in damage done at different armor levels.

Reading the graph is easy! (I hope).  The damage for Graves without runes (but with masteries is calculated).  The red and blue lines you see are the additional damage you get from runes (either AD or arpen) per basic autoattack, or damage with runes minus damage dealt without runes.  The vertical purple line is the average armor of enemies at that level without extra armor items.

Verdict: Attack damage wins against armor penetration at the beginning of the game.

Mid game: level 7 with 2x Doran's Blades

After most AD carries have made their first shopping trip, they usually will end up with 2 Doran's Blades representing an extra 20 damage dealt per autoattack.  At level 7 and with these items, the difference between arpen and AD is much less clear-cut than at the beginning of the game.  Most champions have not bought any defense mitigation items by this point in the game, so it should be safe to assume that enemies average around 50 armor at this time considering average armor scaling.

Whereas earlier in the game damage was always better than armor penetration, the two damage sources nearly break even at the average armor level.  Armor penetration is now stronger than attack damage at lower armor targets (AP carries without armor runes, supports, etc.) while attack damage still holds an advantage versus targets at or above the designated average armor level bruisers and other AD carries).

Verdict: With only minor differences in damage output, AD and arpen runes tie each other in damage output.

Mid game: level 13 with 2x Doran's Blade and an Infinity Edge

With a few more levels and an extra +70 damage from buying an Infinity Edge, armor penetration quickly outpaces extra attack damage for total damage output against most standard targets; however, it does see decreasing returns to damage against high armor targets with AD runes giving a greater increase in damage against targets with more than 175 armor.  At this point in the game, its safe to assume that most of the targets you are attacking don't actually have this much armor yet; even if they do, the difference in damage output isn't large enough for the runes to matter a whole lot.  Against average targets, we will see enough of a marginal damage increase for armor penetration runes to take the edge.

Verdict: With enough extra damage, armor penetration wins out against attack damage for most targets.

End game: level 18 with 2x Doran's Blade, Infinity Edge, and a Last Whisper

When AD carries have enough money to buy a Last Whisper, they generally turn into an unstoppable force.  The same occurs when the 35% armor penetration is combined with armor penetration runes: with a Last Whisper, armor penetration becomes superior to attack damage at every single armor value.  Against a target with no bonus armor and average armor scaling, armor penetration runes allow for a double digit increase in damage dealt per autoattack.

Verdict: Armor penetration is superior at the end of the game.

Final Thoughts

To sum of the findings of today: attack damage runes give greater damage output than armor penetration against enemy champions from level 1 through the midgame until the AD carry starts to build endgame items.  After this point, flat armor penetration runes are much more effective when combined with items because they will increase marginal damage output over the enemy by double digits per autoattack.  Keep in mind that the calculations use the base damage for Graves, although most other carries have similar damage scaling.  I haven't completed mathed out the new items and there may be more optimal AD carry builds for the new season, but keep this general rule of thumb in mind: the more bonus damage you have, the more effective armor penetration is.  

While in the last season attack damage was the clear choice for AD carries (unless you intended to dunk the enemy bot lane at level 2), the new runes introduces a choice for players.  Picking bonus AD now makes you stronger in the early game at the cost of late game effectiveness.  On the other hand, many games are often decided in the first 15 minutes of the game when armor penetration is still ineffective.  Only experimentation with both sets of runes will find the optimal choice for your playstyle.  Which type of rune do you think will be most effective for your personal playstyle?  Early game attack damage, or late game armor penetration? Thanks for reading, and please comment below with your thoughts!

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  • #38 DuskSC2

    these graphs dont make any sense. the armor pens runes are giving massive bonus damage vs targets with 0 armor. i feel like the armor pen part of the graph is upside down. it should start at 0 on every single graph and scale up from there. not start really high and scale down? 

    The last graph also has flat AD runes some how gaining damage, being reduced to only 10 damage instead of around 8 like the previous graphs

    am i reading it wrong?


  • #37 DarkTwinge

    The baseline premise here is flawed: You never want to run ArPen quints on an AD carry.  If you want ArPen, run flat AD quints and some amount of ArPen reds - they stack multiplicatively.  AD quints + ArPen reds breaks even around level 4 and ArPen stays better against champions after that.  Furthermore, abilities should not be ignored, because almost every ADC has a physical damage ability that scales more strongly with ArPen than AD (including Peacemaker with it's 1.3 AD ratio).

    Your statement about why AD was preferred in season 2 is also false - AD is strong because it lets you get last hits; it's pretty much always done less damage than ArPen.  All in all, the end comparison is almost identical to how it was in season 2: AD improves your last hitting (and tower damage slightly), ArPen improves your damage to champions.  The only difference in Season 3 is that they break even slightly later (so AD can have a slight advantage at early levels now, though this is heavily offset by viable builds starting Doran's or Long Sword), and that ArPen is now stronger late game (before it basically broke even again with a full build).

  • #35 Cerbereth

    Flat ad runes are clearly superior. You get a better early game and better last hitting, and by the time armor pen runes would kick in you probably already have last whisper.

    Armor pen runes aren't useless though because people like Garen need them to stop a chain vest from severely gimping their damage.

  • #36 nornamor

    Yes, but the fact that Armorpen now stacks with Last whisper makes Armor pen even stronger that far into the game... the numbers are significant.... + Considering how broken BC is right now...  Armorpen + Brutalizer is will probobly give you a better earlygame than the enemy AD as long as you are capable of lasthitting with less AD.... 

  • #40 Cerbereth

    I generally run mixed pages with flat ad quints and armor pen reds.

  • #34 exacerberus

    Well this was kinda expected, but I enjoyed the article. I suspect that with the +25 base mov speed buff across the board (directly making nerfed boots less attractive starting items), rune setups in S3 are gonna be more varied than the full flat AD or ArPen Marks + flat AD Quits setups everyone was using in S2.

    Lasthitting with a Doran Sword or with a Long Sword is not that hard, so some more lategame-oriented choices may become popular very soon. I'm pretty curious about Long Sword + 2 HP pots start with ArPen Marks and LifeSteal Quints: it sounds solid enough for early lane sustain and it's definitively a beast setup lategame (even more with the ArPen mechanic change and the nerfs to lifesteal itemization).

  • #33 Zulkyr

    I think it's safe to assume that with how cheap attack damage is nowadays I will prefer armor penetration over flat AD. The boost to your ability to last hit doesn't change much for me. I've been playing ADC for about a year now and have no problem doing it with 55-60 AD at lvl 1. I've also been skipping doran's for early pickaxe and and/or vamp scepter so I tend to have a lot of extra AD pretty early.

  • #32 Timecow
    My recollection is that 6 Arpen marks, 3 AD marks, and 3 AD quints was strongest last season. How does that setup pan out now?
  • #28 Stetto

    Nice to see the break even points.

    But I don't think Armor Penetration is more viable than last season. Afaik, everyone picked flat AD, because it's better during early game and allows for easier farming. The early game gap became even bigger, so I don't see how it's a viable choice, unless you think you can win the laning phase anyway, because of jungler ganks or counter picking.

    On the other hand, Armor Penetration works well with physical spells, because of their base damage. Armor Penetration could be strong on Graves, Jayce, Ashe and alike, but some maths to back this theory up would be nice. Maybe you could look into this sooner or later. (I'm capable to do the math myself, but I won't publish it.)

  • #29 TreeBurrow

    Armour Penetration is more viable that it used to be, because Flat AD runes are no longer essential, largely due to the Boots nerf and the Doran's Blade buff...

    You don't HAVE to start with Boots anymore, you're able to start with a Long Sword (Builds into Vamp Sceptre) or a Doran's Blade (Early game sustain was buffed by 100%) since you have the option of buying one of these items, you don't NEED Flat AD Runes, because, if you have 10 AD on your first item, you should be able to CS comfortably...

    Thus, you can use your Quints on anything you desire... ArPen, AS, MS, heck, even Armour... The whole starting strategy of AD carries has changed because of the increased item diversity... There's no reason to stick with what you used to use in Season 2...

    Some people like having 75 AD at level 1... I find it un-needed...

  • #31 Stetto

    That makes a lot of sense. Thank you for your reply.

  • #27 inb4jelly

    (hi hotshot)



    and i knew it was better to use ad now mainly on ad scalers

    Last edited by inb4jelly: 12/6/2012 5:01:36 PM
  • #26 LoreSpydir

    I wonder where the break-even would happen on a brawler build?

  • #25 yoshiwaan

    I don't understand the 1st Graph.

    At 0 armour how can arpen runes give you 16 bonus damage? It doesn't reduce armour below 0.

  • #39 OmgabeeX

    That's because you totally ignored the purple line at 30 armor and what he mentioned in the paragraph. He said "During Season 2, there was a small armor range (30 to 60ish armor)" so the graph actually starts at 30 armor. Everything before that is just showing the starting point of the curves. It doesn't mean anything because the armor is not below 30.

  • #23 acerunner


  • #24 TreeBurrow

    Really? Haha...

    Guess that explains how you became a Pillar

  • #21 KusaKusa

    For measuring abilities, could you also use the graphs?  You could compare the total damage of the ability, (total AD * AD ratio + ability base damage), to the base damage of an auto-attack from the graph (i.e. the total AD).  And then you would divide that by the AD ratio of the ability to get it scaled 1:1 AD ratio like auto-attacks.  Would this work for comparing abilities?

  • #19 fatovarius

    Since I'm a cheapskate and I only have 2 rune pages, I have a mix of 3 armor pen and 6 flat AD marks on my AD rune page. The way I see it, if I do it this way I get the best of both worlds. I can boost my last hit and harass potential early game with flat AD, and still enjoy a bit of armor pen for a smoother transition into late game. Midgame both are important, because you're often firing on champs that have more than 50 armor (i.e. not the enemy ADC) so you're going to want at least a little bit of extra armor pen before you itemize for it late game, and of course the flat AD is still a significant enough amount at that stage in the game that boosts your overall damage in teamfights by a noticeable amount.


    Time for some pulled out of my ass math. I tried to be conservative as to the possible damage output of a graves at level 13 to help illustrate the benefit of even a little extra AD. Note that not everyone has such good AD ratios on their skills, so your favorite ADC champ may vary wildly from this formula. It pays to do your own math in this regard. DISCLAIMER OVER.

    Assuming graves again with the +5.7 damage from 6 flat AD marks with that, let's say you hit 2 champs with 2 buckshots, 1 with your ulti, and you get off 8 autoattacks in a teamfight. With the bonus AD on my marks alone I am looking at 45.6 damage from autoattacks, (roughly) 27.4 from buckshot, and 14.8 from the ulti. That's 87.8 extra damage per teamfight with only 6 marks and no quints. Armor mitigates that damage a decent amount, but the combination of armor pen from the other 3 marks and masteries, you're still doing almost all of your damage, and what damage you don't do is probably just as much as having 6 flat AD marks helps you. I'm not going to do THAT math, however. I have work to look for.

  • #18 TreeBurrow

    Great article, but not comprehensive enough... I'm always left wanting more...

    • How do ArPen Runes in S3 differ from ArPen Runes in S2? Is the late game damage increase more or less than it used to be, when compared to Flat AD? (Considering the change to the ArPen formula as well as the decrease in ArPen from 25 to 19)
    • How do Scaling AD Runes now compare to ArPen Runes at all stages of the game? (Since'many people are now starting with Long Swords or Doran's Blades, they don't need the Flat AD from Runes in order to last hit effectively)
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