FOR SCIENCE: The Worth of Your Runes (Patch 4.3 Vel'Koz Patch)

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Where we will keep you updated with all the math behind League of Legends. We will give you an overview of the current best builds (backed up by formulas) and if you have any League related questions, feel free to ask and we'll settle them ASAP, all to help you get up in the ranks!

Today we will be looking at the gold efficiency of your runes. But, in order to do this, we have to first find out the average cost of each stat.

To simplify things, we will only be looking at the Quints. If you want to know the costs of the other runes, just take the gold efficiency value for whichever stat you're doing it for and multiply it by the amount the rune gives (just follow the examples below if it still doesn't make sense).

So let's begin:

Let's look at the cost of some stats by looking at the in game items:

Ability Power
Amplifying Tome gives +20AP for 435g, so (435g/20AP)=21.75g per AP
Needlessly Large Rod gives +80AP for 1600g, so (1600g/80)=20g per AP
The average of these two comes out to (21.75g+20g)/2=20.875g per AP

Armor
Cloth Armor gives +15Armor for 300g, so (300g/15Armor)=20g per Armor
Chain Vest gives +40Armor for 720g, so (720g/40Armor)=18g per Armor
The average of these two comes out to (20g+18g)/2=19g per Armor

Armor Penetration
The Brutalizer gives +25AD, +10%CDR, and +10ArmPen for 1337g. At 36g per AD (refer below) and 19.3505g per %CDR (refer below), we get ((36g*25AD)+(19.3505g*10%CDR))=(900g+193.505g)=1093.505g worth of AD and %CDR. We get (1337g-1093.505g)=243.495g worth of ArmPen. So, (243.495g/10ArmPen)=24.3495g per ArmPen

Attack Damage
Long Sword gives +10AD for 360g, so (360g/10AD)=36g per AD
B.F. Sword gives +45AD for 1550g, so (1550g/45AD)=34.44g per AD
The average of these two comes out to (36g+34.44g)/2=35.22g per AD

Attack Speed
Dagger gives +12%AS for 400g, so (400g/12%AS)=33.33g per %AS
Recurve Bow gives 30%AS for 900g, so (900g/30%AS)=30g per %AS
The average of these two comes out to (33.33g+30g)/2=31.665g per %AS

Cooldown Reduction
Fiendish Codex gives +30AP and +10%CDR for 820g. At 20.875g per AP (refer above), we get (20.875g*30AP)=626.25g worth of AP and (820g-626.25g)=193.75g worth of %CDR. So, (193.75g/10%CDR)=19.375g per %CDR

Ionian Boots of Lucidity gives +45MS and 15%CDR for 1000g. At 13g per MS (refer below), we get (13g*45MS)=585g worth of MS and (1000g-585g)=415g worth of %CDR. So, (415g/15%CDR)=27.667g per %CDR

Kindlegem gives +200HP and +10%CDR for 850g. At 2.649g per HP (refer below), we get (2.649g*200HP)=529.8g worth of HP and (850g-529.8g)=320.2g worth of %CDR. So, (320.2g/10%CDR)=32.02g per %CDR

Stinger gives +40%AS and +10%CDR for 1250g. At 31.665g per %AS (refer above), we get (31.665g*40%AS)=1266.6g worth of %AS and (1250g-1266.6g)=-16.6g worth of %CDR. So, (-16.6g/10%CDR)=-1.66g per %CDR

The average of these four comes out to (19.375g+27.667g+32.02g-1.66g)/4=19.3505g per %CDR

Critical Strike Chance
Brawler's Gloves gives 8%Crit for 400g, so (400g/8%Crit)=50g per %Crit
Cloak of Agility gives 15%Crit for 730g, so (730g/15%Crit)=48.667g per %Crit
The average of these two comes out to (50g+48.667g)/2=49.33g per %Crit

Health
Ruby Crystal gives +150HP for 400g, so (400g/150HP)=2.667g per HP
Giant's Belt gives +380HP for 1000g, so (1000g/380HP)=2.63157g per HP
The average of these two comes out to (2.667g+2.63157g)/2=2.649g per HP

Health Regen
Rejuvenation Bead gives +5HP5 for 180g, so (180g/5HP5)=36g per HP5

Life Steal
Vampiric Scepter gives +10AD and +10%LS for 800g. At 35.22g per AD (refer above), we get (35.22g*10AD)=352.2g worth of AD and (800g-352.2g)=447.8g worth of %LS. So, (447.8g/10%LS)=44.78g per %LS

Magic Penetration
Sorcerer's Shoes gives +45MS and +15MPen for 1100g. At 13g per MS (refer below), we get (13g*45MS)=585g worth of MS and (1100g-585g)=515g worth of MPen. So,
(515g/15MPen)=34.33g per MPen

Magic Resist
Null-Magic Mantle gives +20MR for 400g, so (400g/20MR)=20g per MR
Negatron Cloak gives +40MR for 720g, so (720g/40MR)=18g per MR
The average of these two comes out to (20g+18g)/2=19g per MR

Mana
Sapphire Crystal gives +200MP for 400g, so (400g/200MP)=2g per MP

Mana Regen
Faerie Charm gives +3MP5 for 180g, so (180g/3MP5)=60g per MP5

Movement Speed
Boots of Speed gives +25MS for 325g, so (325g/25MS)=13g per MS

Spell Vamp
Hextech Revolver gives +40AP and 12%SV for 1200g. At 20.875g per AP (refer above), we get (20.875g*40AP)=835g worth of AP and (1200g-835g)=365g worth of %SV. So, (365g/12%SV)=30.4167g per %SV

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Now that we have the costs of all the stats, we can finally calculate the gold efficiency of each rune!
Note: Some of them are currently too hard to calculate and we will save them for another day :(

AGAIN THESE ARE ALL QUINTESSENCES TO SAVE TIME, JUST PLUG AND CHUG NUMBERS FROM ABOVE TO CALCULATE COSTS OF OTHER RUNES!

Attack Damage: (35.22g*2.25AD)=79.245g

Attack Damage per Level: (35.22g*0.25AD)=8.805g per level, 158.49g at level 18

Ability Power: (20.875g*4.95AP)=103.33125g

Ability Power per Level: (20.875g*0.43AP)=8.97625g per level, 161.5725g at level 18

Attack Speed: (31.665g*3.4%AS)=107.661g

Armor: (19g*4.26Armor)=80.94g

Armor per Level: (19g*0.38Armor)=7.22g per level, 129.96g at level 18

Armor Penetration: (24.3495g*2.56ArmPen)=62.33472g

Cooldown Reduction: (19.3505g*1.67%CDR)=32.315335g

Cooldown Reduction per Level: (19.3505g*0.14%CDR)=2.70907g per level, 48.76326g at level 18

Critical Chance: (49.33g*1.86%Crit)=91.7538g

Health: (2.649g*26HP)=68.874g

Health per Level: (2.649g*2.7HP)=7.1523g per level, 128.7414g at level 18

Health Regen: (36g*0.43HP5)=15.48g

Health Regen per Level: (36g*0.11HP5)=3.96g per level, 71.28g at level 18

Hybrid Penetration: (24.3495g*1.79ArmPen)+(34.33g*1.4MPen)=43.585605g+48.062g=91.647605g

Lifesteal: (44.78g*2%LS)=89.56g

Magic Penetration: (34.33g*2.01MPen)=69.01g

Magic Resist: (19g*4MR)=76g

Magic Resist per Level: (19g*0.37MR)=7.03g per level, 126.54g at level 18

Mana: (2g*37.5MP)=75g

Mana per Level: (2g*4.17MP)=8.34g per level, 150.12g at level 18

Mana Regen: (60g*0.41MP5)=24.6g

Mana Regen per Level: (60g*0.065MP5)=3.9g per level, 70.2g at level 18

SpellVamp: (30.4167g*2%SV)=60.8334g

So the runes that cost the highest gold are the most gold efficient. Of course, it also depends on how effective your champion is with these stats.

Hope this helped!

Add me in game if you have any questions, or feel free to ask here.
IGN: Knows Gogeta SS4