How Stuff Works: Armor Class

Dzarn, one of EQ’s developers, contributed a stellar post on the official EverQuest forums describing the math behind armor class here. Since that 2014 post, changes were made to displayed AC to show players real values instead. This guide provides updated references to AC computations, and also includes corrections to several flaws found in Dzarn’s original computations.

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AC Basics

Armor class affects a player by both reducing the amount of melee damage they receive (mitigation) and reducing the chance of hits successfully landing on them (evasion, aka, avoidance). A simple way of understanding what AC does in combat for you is the following::

  • Your Mitigation -vs- NPC’s Attack Rating
  • Your Evasion -vs- NPC’s Accuracy

Displayed AC Values – Then and Now

If you open up your inventory window (clicking the “i” key on your keyboard), you will see two values displayed for “AC.” The left value is for mitigation and the right value is for evasion.

  1. Mitigation AC – the left-side value, is your computed value for taking less melee damage
  2. Evasion AC – the right-side value, is your computed value for avoiding melee damage

Prior to the January 18, 2017 patch, Displayed AC only showed one value. Once the patch was implemented, players complained about seeing lower AC values, when in fact they were seeing their “real” computed values instead.

The calculations behind AC have largely remained intact over the years (except for some minor bugs/fixes). The values displayed for you should theoretically be the “real” numbers, but we will go over the math in the next three sections to understand better how it is all computed by EQ.

Here is my Level 120 Shadow Knight as example:

  • Displayed Mitigation AC = 10,119
  • Displayed Evasion AC = 3861

Mitigation AC at a Glance

When most players discuss AC matters, they are most often referring to Mitigation AC. This displayed value is the direct result of the following:

  • ‘Mitigation AC’ = Soft Cap AC + Post Cap AC

Soft Cap and Post Cap AC utilizes your AC SUM, which is a total of computed AC points from a several areas such as Worn AC and Spell AC, to name a few. It is a much more involved number to compute as you will see shortly.

Evasion AC at a Glance

Also referred to as “Computed Defense,” Evasion AC requires less computational work to display your value. It’s a much more straightforward number to compute. For this reason, a majority of this guide will be devoted to discussing Mitigation AC.

Calculations: AC SUM

These are the steps to calculate your AC SUM. There is also a shortcut discussed under the AC SUM section to obtain this number differently.

‘Worn AC’ Calculations

  • Step 1 = 0 (this value is set for players NOT in shrouded form)
  • Step 2 = Sum of all AC stats on equipped gear (excluding ammo slot)
  • Step 3 = ‘Food AC’ + ‘Drink AC’
  • Step 4 = ‘Tribute AC’ + ‘Trophy AC’ + ‘Guild Tribute AC’ + ‘Guild Trophy AC’
  • Step 5 = Step 1 + Step 2 + Step 4 + Step 5
  • Step 6 = (Step 5 * 4) / 3

Anti-Twink Calculations

Players below level 50 receive a Hard Cap.

  • If ‘Player Level’ < 50 and Step 6 > [25 + (6 * ‘Player Level’)]
    • Step 7 = [25 + (6 * ‘Player Level’)]
  • Otherwise: Step 7 = Step 6

Race and Class AC Bonus Calculations

Applicable to Iksars, Monks, Beastlords, and Rogues.

  • Step 8 = Step 7 + ‘Race Bonus’ + ‘Class Bonus’

NPC and Pet Calculations

Code that deals with server-side mobs/NPCs (if you are curious). This will obviously not apply to a player, so Step 10 = Step 8, and you can move on to Step 11.

  • Step 9 = Step 8 + ‘NPC Base AC’
  • Step 10 = Step 9 + ‘Owners Pet AC AAs’

‘Defense Skill’ Calculations

  • If you are a SILK Class:
    • Step 11 = ‘Defense Skill’ / 2
  • Otherwise:
    • Step 11 = ‘Defense Skill’ / 3
  • Step 12 = Step 10 + Step 11

‘Spell AC’ Calculations (Includes Item AAs)

  • Step 13 = ‘SPA 1 Buffs’ + ‘SPA 416 Buffs’
  • Step 14 = ‘Form of Defense’ + ‘Prismatic Ward’
  • If you are a SILK Class:
    • Step 15 = (Step 13 + Step 14) / 3
  • Otherwise:
    • Step 15 = (Step 13 + Step 14) / 4
  • Step 16 = Step 12 + Step 15

‘Armor of Wisdom’ AA Calculations

Some of these steps look redundant, but I left them intact in the event that EQ devs make changes in the future to the class division numbers used for AoW.

  • If you are an ENC, MAG, NEC, or WIZ:
    • Step 17 = ‘Armor of Wisdom’ / 3
  • If you are a BRD, CLR, MNK, or RNG:
    • Step 17 = ‘Armor of Wisdom’ / 4
  • If you are a BST, BER, DRU, ROG, or SHM:
    • Step 17 = ‘Armor of Wisdom’ / 4
  • If you are a PAL or SHD:
    • Step 17 = ‘Armor of Wisdom’ / 4
  • If you are a WAR:
    • Step 17 = ‘Armor of Wisdom’ / 4
  • Step 18 = Step 16 + Step 17

‘Hero’s Fortitude’ AA Calculations

  • If you are a SILK Class:
    • Step 19 = (‘Hero’s Fortitude’) / 3
  • Otherwise:
    • Step 19 = (‘Hero’s Fortitude’) / 4
  • Step 20 = Step 18 + Step 19

Agility Bonus Calculations

You get an Agility Bonus to AC if your ‘Functional Agility’ is over a computed value of 70. By completing the last step, you also have your AC SUM.

  • ‘Functional Agility’ = AGI + hAGI
  • If ‘Functional Agility’ > 70:
    • Step 21 = ‘Functional Agility’ / 20
  • Otherwise:
    • Step 21 = 0
  • ‘AC SUM’ = Step 20 + Step 21
Calculations: Mitigation AC

Once you obtain your AC SUM you can then use it to compute your Mitigation AC.

Soft Cap AC Calculations

  • Step 1 = [‘Base AC’ * (‘Combat Stability’ + ‘Physical Enhancement’)] / 100
  • Step 2 = truncate(‘Base AC’ + Step 1)

Further Soft Cap AC Calculations for an Equipped Shield

  • Step 3 = Shield AC + (Heroic Strength / 10)
  • Step 4 = Step 2 + Step 3

Post Cap AC Calculations

If ‘AC SUM’ > Step 4:

  • Step 5 = ‘AC SUM’ – Step 4
  • Step 6 = Step 4 + (Step 5 * ‘Soft Cap Multiplier’)
  • Step 7 = truncate(Step 6)
  • ‘Mitigation AC’ = Step 7

Otherwise: ‘Mitigation AC’ = AC SUM

Calculations: Evasion AC

Evasion AC number is also known as your “Computed Defense” value.

All Calculation Steps for Evasion AC

  • Step 1 = (‘Defense Skill’ * 400) / 225
  • Step 2 = Step 1 + ‘Agility Bonus’
  • Step 3 = Step 2 + ‘Item Avoidance’
  • Step 4 = truncate(Step 3 * ‘Drunkenness Reduction’)
  • Step 5 = Step 4 + 10
  • Step 6 = truncate(Step 5 * ‘AA Avoidance’)

Finally, you have the ‘Computed Defense’ value which is the Displayed Evasion AC. This last check is done to avoid a negative number, most likely if you are under a detrimental effect.

  • If Step 6 < 1: ‘Computed Defense’ = 1
  • Otherwise, ‘Computed Defense’ = Step 6

Calculating Your Agility Bonus

This part will involve a series of sub-steps to find your Agility Bonus value. It uses your regular AGI stat and Heroic Agility stat values.

Functional Agility – is the capped Agility stat plus Heroic Agility. This value will be used in the Agility Bonus calculation.

  • ‘Functional Agility’ = AGI + hAGI

The Agility Bonus will then be calculated as follows:

  • AB Step 1 = [8000 * (‘Functional Agility’ – 40)] / 36000
  • AB Step 2 = (‘Heroic Agility’ / 10)
  • ‘Agility Bonus’ = AB Step 1 + AB Step 2

Finding Your Item Avoidance

Your Item Avoidance number is really your mod2 avoidance stat found under the “Heroic Mods” section of your stat window. For lower level players, mod2 is capped at 100 until 400 points of Heroic Agility is obtained.

If you are capped, then you have to use the capped number (ie: 100).

Calculating Your Drunkenness Reduction (Multiplier)

If you look at your Displayed Evasion AC while consuming alcohol, the moment the number drops, it means your Drunkenness Reduction (which acts as a multiplier) is taking effect.

The amount of “How Drunk” you can be is a range from 0-200. Each drink adds a fixed amount based on your alcohol tolerance skill.

  • ‘Drunk Value’ = ‘How Drunk’ / 2
  • ‘Drunkenness Reduction’ = (110 – ‘Drunk Value’) / 100.0
  • If ‘Drunkenness Reduction’ > 1.0: ‘Drunkenness Reduction’ = 1.0

AA Avoidance

There are two AAs that passively increase melee avoidance as percentages.

  • Combat Agility (CA) – Rank 87 (ToL expansion): Increases avoidance by 105%
  • Physical Enhancement (PE) – Rank 15 (RoS expansion): Increases avoidance by 15%

In order to calculate Passive Avoidance, we need to convert the percentages into working numbers (because… programming). The equation to use:

  • ‘AA Avoidance’ = (100 + CA + PE) / 100
AC SUM

Raw AC obtained from gear does not affect you the same way as raw AC from buffs and AAs. This is why numerous steps are involved to calculate your AC SUM. AC SUM is a cumulative total of computed AC stemming from calculations done in the following areas:

  1. Worn AC – includes gear, stat food/drink, activated tribute, and activated trophies
  2. Race and AC Bonuses
  3. Defense Skill
  4. Spell AC – includes spell buffs and passive ‘Item’ AAs
  5. Armor of Wisdom (AA)
  6. Heroic Fortitude (AA)
  7. Agility Bonus

Once the AC SUM is computed, then Soft Cap AC and Post Cap AC will be used to compute your final Mitigation AC value.

Alternate Way to Compute AC SUM

Considering we already have the Displayed Mitigation AC number, there is a way to work backwards with it and get the AC SUM:

  1. Compute your Soft Cap AC
  2. Post Cap AC = Mitigation AC – Soft Cap AC
  3. AC SUM = (Post Cap AC / Soft Cap Multiplier) + Soft Cap AC

Computing the AC SUM this way will most likely result in a decimal number. Since we’re using a non-programmatic approach here, you must round UP the decimal. Keep in mind that when we went over the programmatic steps, numbers were truncated instead.

Using this shortcut can give you a fall-back method to check against your calculations and see if any errors/discrepancies/bugs exist.

Soft Cap AC

Your Soft Cap AC dictates how much of your AC SUM is used at full value. It is computed from the following:

  • Base AC
  • Combat Stability (AA)
  • Physical Enhancement (AA) – available only to melee classes
  • Shield (if equipped)

Base AC

Everyone has an initial starting point of Soft Cap AC. This is known as the Base AC. This is a predetermined value corresponding to class and level.

Searching Your Base AC Number

Inside your Everquest > Resources subfolder, there is a file called ACMitigation.txt. Once the file is opened, there is a line at the top: #CLASS^LVL^AC_CAP^SOFT_CAP_MULTIPLIER^

For now, we’re concerned with this portion: #CLASS^LVL^AC_CAP

  • #CLASS refers to the assigned class ID
  • LVL refers to your character’s level
  • AC_CAP refers to the Base AC number

On the left-hand side of the list, the first numbers on each line are IDs corresponding to each class in game. The IDs represent the following classes:

  • 1=Warrior
  • 2=Cleric
  • 3=Paladin
  • 4=Ranger
  • 5=Shadowknight
  • 6=Druid
  • 7=Monk
  • 8=Bard
  • 9=Rogue
  • 10=Shaman
  • 11=Necromancer
  • 12=Wizard
  • 13=Magician
  • 14=Enchanter
  • 15=Beastlord
  • 16=Berserker

For warriors, Base AC numbers will be listed first. Every line that begin with a “1” will tell a warrior what their Base AC number is corresponding to level (LVL). This is why the list is so long in the text file, since it accounts for every single level up to current max level per class.

Passive AA Abilities

Your Soft Cap AC will be pushed beyond your Base AC once you obtain ranks of Combat Stability and Physical Enhancement. The latter is only available to melee classes.

  • Combat Stability – Rank 93 (ToL expansion): Increases Soft Cap AC by 120%
  • Physical Enhancement – Rank 12 (RoS expansion): Increases Soft Cap AC by 25%

Shields

If you heard rumors that an equipped shield is worth about three times it’s AC versus other pieces of gear, it is true. Since augs become part of a shield’s value, using the best AC aug can boost it’s Soft Cap value further. A shield will apply two direct increases to Soft Cap AC:

  • Value of AC on shield directly increases Soft Cap
  • hSTR in your stat window, divided by 10, provides another Soft Cap increase

Besides increases to Soft Cap AC, a shield will also get computed a third time into worn AC.

How to Calculate Your Soft Cap AC

  • Step A = [‘Base AC’ * (‘CS’ + ‘PE’)] / 100
  • Step B = ‘Base AC’ + Step A
  • Step C = Shield AC + (Heroic Strength / 10)
  • Soft Cap AC = Step B + Step C

As an example, my level 120 Shadow Knight has the following:

  1. Base AC of 738: Obtained from 5^120^738^0.33^ in the ACMitigation.txt file
  2. Rank 93 of Combat Stability – increase to Soft Cap AC by 120%
  3. Rank 12 of Physical Enhancement – increase to Soft Cap AC by 25%
  4. Equipped Shield AC is 870
  5. Heroic Strength is 1504

The numbers plugged in look like this:

  • Step A = [738 * (120 + 25)] / 100
  • Step B = 738 + 1070
  • Step C = 870 + (1504 / 10)
  • Soft Cap AC = 1808 + 1020
  • Soft Cap AC = 2828 for my SK
Post Cap AC

AC SUM points past the Soft Cap AC will receive diminished returns per point of AC. This results in your Post Cap AC. Similar to Base AC, the Post Cap AC is computed differently by class (but not level) and is based on what is known as a Soft Cap Multiplier.

Finding Your Soft Cap Multiplier

Refer again to the ACMitigation.txt file. This time, we will review the entire line item corresponding to class: #CLASS^LVL^AC_CAP^SOFT_CAP_MULTIPLIER^

These are the multipliers you should see for each class:

  • Warrior = 0.35
  • Cleric = 0.3
  • Paladin = 0.33
  • Ranger = 0.315
  • Shadowknight = 0.33
  • Druid = 0.265
  • Monk = 0.3
  • Bard = 0.3
  • Rogue = 0.28
  • Shaman = 0.28
  • Necromancer = 0.25
  • Wizard = 0.25
  • Magician = 0.25
  • Enchanter = 0.25
  • Beastlord = 0.28
  • Berserker = 0.28

If you were to look at an SK’s 0.33 multiplier, it basically tells us that each point of AC that exceeds the SK’s Soft Cap will be treated as 0.33 AC instead.

How to Calculate Your Post Cap AC

First, you need to know your Soft Cap AC in order to compute what happens to AC after that soft cap is reach. Next, you’ll need to know your AC SUM. If you don’t know your AC SUM, don’t worry – we’ll use my level 120 Shadow Knight as an example.

My level 120 Shadow Knight has the following:

  • Soft Cap AC value of 2828
  • Has a Soft Cap Multiplier of 0.33
  • Has an AC SUM of 24,922

My AC SUM is greater than my Soft Cap AC, which means I am certainly using Post Cap AC.

  • Step A = ‘AC SUM’ – ‘Soft Cap AC’
  • Step B = Step A * ‘Soft Cap Multiplier’
  • Post Cap AC = truncate(Step B)

My values will be computed like this:

  • Step A = 24,922 – 2828
  • Step B = 22,094 * 0.33
  • Post Cap AC = truncate(7291.02)
  • Post Cap AC = 7291 for my SK

Checking the Math

My SK’s Displayed Mitigation AC is 10,119, if you recall:

  • ‘Mitigation AC’ = Soft Cap AC + Post Cap AC

If we plug in my Soft Cap AC and Post Cap AC:

  • 10,119 = 2828 + 7291
Race/Class AC Bonuses

Racial and Class AC Bonuses are applicable to Iksars, Monks, Beastlords, and Rogues.

Iksar AC Bonus

Iksars are the only race that get an AC Bonus. It caps at 35 AC once you hit level 35:

  • RaceBonus = PlayerLevel
  • If RaceBonus < 10: = 10
  • If RaceBonus > 35: = 35

Monk AC Bonus and Penalty

Based on a monk’s level, total weight can yield either an AC bonus or a penalty. The confirmed Hard Cap and Soft Cap Weights for a Monk are displayed below:

  • Level 100: Hard Cap Weight 58: Soft Cap Weight 35
  • Level 95: Hard Cap Weight 57: Soft Cap Weight 34
  • Level 90: Hard Cap Weight 56: Soft Cap Weight 33
  • Level 85: Hard Cap Weight 55: Soft Cap Weight 32
  • Level 80: Hard Cap Weight 54: Soft Cap Weight 31
  • Level 75: Hard Cap Weight 53: Soft Cap Weight 30
  • Level 70: Hard Cap Weight 53: Soft Cap Weight 28
  • Level 65: Hard Cap Weight 53: Soft Cap Weight 26
  • Level 64: Hard Cap Weight 50: Soft Cap Weight 24
  • Level 62: Hard Cap Weight 47: Soft Cap Weight 24
  • Level 60: Hard Cap Weight 45: Soft Cap Weight 24
  • Level 55: Hard Cap Weight 40: Soft Cap Weight 20
  • Level 51: Hard Cap Weight 38: Soft Cap Weight 18
  • Level 45: Hard Cap Weight 36: Soft Cap Weight 17
  • Level 30: Hard Cap Weight 34: Soft Cap Weight 16
  • Level 15: Hard Cap Weight 32: Soft Cap Weight 15

It’s assumed that every 5+ levels over level 100 will most likely continue to scale Hard Cap and Soft Cap weights by 1.

1. If total weight is less than the Soft Cap Weight:

  • ClassBonus = Player Level + 5
  • (4 * ClassBonus) / 3 = ClassBonus

2. If total weight is greater than the Soft Cap Weight, but less than the Hard Cap Weight:

  • ClassBonus = PlayerLevel + 5
  • If Weight > SoftCap:
  • Reduction = (Weight – SoftCap) * 6.66667
  • If Reduction > 100.0: = 100.0
  • Reduction = (100 – Reduction) / 100
  • ClassBonus = ClassBonus*Reduction
  • If ClassBonus < 0: = 0
  • (4 * ClassBonus) / 3 = ClassBonus

3. If total weight is greater than the Hard Cap Weight, then a Penalty AC is incurred:

  • Penalty = PlayerLevel +5
  • Multiplier = (Weight – (HardCap-10.0))/100.0
  • If Multiplier > 1.0: = 1.0
  • Penalty = (4 * Penalty) / 3
  • Penalty = Multiplier * Penalty

Rogue AC Bonus

Past level 30, rogues get a small AC Bonus if their agility is greater than 75 points. This AC Bonus caps at 12 points for them.

  • LevelScaler = PlayerLevel – 26
  • If Agility < 80: ACBonus = (LevelScaler * 1) / 4
  • If Agility < 85: ACBonus = (LevelScaler * 2) / 4
  • If Agility < 90: ACBonus = (LevelScaler * 3) / 4
  • If Agility < 100: ACBonus = (LevelScaler * 4) / 4
  • If Agility >= 100: ACBonus = (LevelScaler * 5) / 4
  • If ACBonus > 12: = 12

Beastlord AC Bonus

Past level 10, beastlords get a small AC Bonus. It operates on a similar principle to rogues, but the AC Bonus caps at 16 points.

  • LevelScaler = PlayerLevel – 6
  • If Agility < 80: ClassBonus = (LevelScaler * 1) / 5
  • If Agility < 85: ClassBonus = (LevelScaler * 2) / 5
  • If Agility < 90: ClassBonus = (LevelScaler * 3) / 5
  • If Agility < 100: ClassBonus = (LevelScaler * 4) / 5
  • If Agility >= 100: ClassBonus = (LevelScaler * 5) / 5
  • If ClassBonus > 16: = 16
AA and Spell AC

AC points from player buffs and passive ‘Item’ AAs are considered ‘Spell AC.’ This type of AC is calculated differently than Worn AC from gear, and it also varies if you are a SILK class or not.

There are other AAs, too, in the form of Armor of Wisdom and Hero’s Fortitude. While these abilities act in a similar manner to ‘Spell AC’, they are used in different steps of AC SUM calculations (and are not lumped together).

‘Spell AC’

These all have AC components which yield the same raw AC points for all players, regardless of class. Unfortunately, you can’t “see” the raw AC points in their descriptions, and you will have to refer to raidloot.com to obtain some of their values.

  • Player Buffs – with AC components and which are too many to list here.
  • Item: Form of Defense – all classes get 2580 raw AC points at rank 31.
  • Item: Prismatic Ward – all classes get 2410 raw AC points at rank 33.

Passive AAs Item: Form of Defense and Item: Prismatic Ward are lumped together here with player buffs, since these act as clicky buffs before they are awarded to you as passive AAs.

Hero’s Fortitude AA

A progression-based AA, but it acts similar to other Spell AC discussed. You cannot see it’s raw value. However, the ranks give the same confirmed raw value below:

  • All classes get 10 raw AC points per rank.

Unlike all buffs and passive item AAs, Hero’s Fortitude is used in separate calculation steps when computing AC SUM. I suspect the reason for this is due in part to how decimals are truncated after division numbers. I attempted to lump this AA in, out of curiosity, with Item AAs (I was buffless) and I ended up with an AC SUM that was off by a single digit each time.

Armor of Wisdom AA

This is another AA ability that is used in separate steps of AC SUM calculations by itself and cannot be lumped together with Spell AC. It also varies per class in the raw value of AC it provides per rank. As a reference, below is a list of how the ranks work per class:

WAR – Rank 50 yields a total of 5630 AC points.

  • Rank: 31 (TBL exp) through 50 (ToL exp) – yields 200 AC points per rank
  • Rank: 22 (EoK exp) through 30 (RoS exp) – yields 100 AC points per rank
  • Rank: 11 (VoA exp) through 21 (TDS exp) – yields 40 AC points per rank
  • Rank: 1 (SoD exp) through 10 (UF exp) – yields 29 AC points per rank

PAL, SHD (Knights) – Rank 50 yields a total of 5150 AC points.

  • Rank: 31 (TBL exp) through 50 (ToL exp) – yields 180 AC points per rank
  • Rank: 22 (EoK exp) through 30 (RoS exp) – yields 90 AC points per rank
  • Rank: 12 (VoA exp) through 21 (TDS exp) – yields 40 AC points per rank
  • Rank: 11 (VoA exp) – yields 30 AC points
  • Rank: 1 (SoD exp) through 10 (UF exp) – yields 31 AC points per rank

BRD, CLR, MNK, RNGRank 50 yields a total of 3955 AC points.

  • Rank: 31 (TBL exp) through 50 (ToL exp) – yields 130 AC points per rank
  • Rank: 22 (EoK exp) through 30 (RoS exp) – yields 65 AC points per rank
  • Rank: 11 (VoA exp) through 21 (TDS exp) – yields 40 AC points per rank
  • Rank: 1 (SoD exp) through 10 (UF exp) – yields 33 AC points per rank

BST, BER, ROG, SHM – Rank 50 yields a total of 3045 AC points.

  • Rank: 31 (TBL exp) through 50 (ToL exp) – yields 90 AC points per rank
  • Rank: 22 (EoK exp) through 30 (RoS exp) – yields 45 AC points per rank
  • Rank: 1 (SoD exp) through 21 (TDS exp) – yields 40 AC points per rank

DRU, ENC, MAG, NEC, WIZRank 50 yields a total of 1940 AC points.

  • Rank: 32 (TBL exp) through 50 (ToL exp) – yields 40 AC points per rank
  • Rank: 22 (VoA exp) through 31 (TBL exp) – yields 20 AC points per rank
  • Rank: 13 (VoA exp) through 21 (TDS exp) – yields 40 AC points per rank
  • Rank: 12 (VoA exp) – yields 60 AC points
  • Rank: 11 (VoA exp) – yields 40 AC points
  • Rank: 1 (SoD exp) through 10 (UF exp) – yields 50 AC points per rank
Testing: AC SUM

We’re going on a journey to find the AC SUM from scratch. It won’t be pretty, but hopefully it helps someone out through the computational steps.

My level 120, Dark Elf, Shadow Knight will be used for all steps.

Gear AC Calculations

  1. I’m not in a shrouded form.
  2. The first thing I did was add up all the AC I saw in my 22 slots of equipped gear. This includes my Power Source (and excludes my ammo slot). I got a total of 16,624.
  3. Since I’m cheap and lazy, I don’t have any AC food/drink.
  4. Since I’m extra cheap and lazy, I also don’t have any activated tribute nor trophies.

Knowing these values, I can plug them in as follows:

  • Step 1 = 0
  • Step 2 = 16,624
  • Step 3 = 0 + 0
  • Step 4 = 0 + 0 + 0 + 0
  • Step 5 = 0 + 16,624 + 0 + 0
  • Step 6 = (16,624 * 4) / 3
  • Step 6 = 22,165

Anti-Twink Code Calculations

I’m level 120 (above level 49), so none of this applies.

  • Step 7 = Step 6
  • Step 7 = 22,165

Race and Class AC Bonus Calculations

I’m a Dark Elf and a Shadow Knight. None of the bonuses here apply to me.

  • Step 8 = Step 7
  • Step 8 = 22,165

NPC and Pet Calculations

I’m not an NPC nor someone’s Pet. None of this applies to me, either.

  • Step 10 = Step 8
  • Step 10 = 22,165

Defense Skill Calculations

This part is simple. All I need to do is open my Skill window and look up my defense value.

  • If you are a SILK Class: FALSE (I’m a Shadow Knight, hello?)
  • Otherwise:
    • Step 11 = 450 / 3
  • Step 12 = 22,165 + 150
  • Step 12 = 22,315

Spell Buffs and AA Calculations

I don’t have any player buffs on me. But I do have the following:

  • Rank 31 of Item: Form of Defense XXXI – yields 2580 raw AC
  • Rank 33 of Item: Prismatic Ward XXVIII – yields 2410 raw AC

The numbers will be plugged in accordingly:

  • Step 13 = 0 + 0
  • Step 14 = 2580 + 2410
  • If you are a SILK Class: FALSE (duh, I am a Shadow Knight)
  • Otherwise:
    • Step 15 = ( 0 + 4990) / 4
  • Step 16 = 22,315 + 1247
  • Step 16 = 23,562

Armor of Wisdom Calculations

I have Rank 46 of Armor of Wisdom. It yields 4430 raw AC.

  • If you are a PAL or SHD:
    • Step 17 = 4430 / 4
  • Step 18 = 23,562 + 1107
  • Step 18 = 24,669

Hero’s Fortitude AA Calculations

I have rank 47 of Hero’s Fortitude. It yields 470 raw AC.

  • If you are a SILK Class: FALSE
  • Otherwise:
    • Step 19 = 470 / 4
  • Step 20 = 24,669 + 117
  • Step 20 = 24,786

Agility Bonus Calculations

My AGI (which is capped) and Heroic Agility are used here:

  • AGI (capped) is 1015
  • hAGI is 1722

Now, we can plug in these values below:

  • ‘Functional Agility’ = 1015 + 1722
  • If ‘Functional Agility’ > 70: (this is definitely, TRUE)
    • Step 21 = 2737 / 20
  • ‘AC SUM’ = 24,786 + 136

Woohoo! We have my AC SUM:

  • ‘AC SUM’ = 24,922
Testing: Mitigation

Now that we obtained my level 120 Shadow Knight’s AC SUM, we can use it to compute my Mitigation AC. I already know my Displayed Mitigation AC is 10,119, but I want to see how these steps check against it.

Soft Cap AC Calculations

I have the following for these steps:

  • Base AC of 738 – according to the ACMitigation.txt file
  • Rank 93 of Combat Stability AA – increases soft cap by 120%
  • Rank 12 of Physical Enhancement AA – increases soft cap by 25%

I can then plug in my numbers below:

  • Step 1 = [738 * (120 + 25)] / 100
  • Step 2 = 738 + 1070
  • Step 2 = 1808

Equipped Shield to Soft Cap AC Calculations

I have an equipped shield, and these are my values for this section:

  • 870 Shield AC
  • 1504 Heroic Strength – value from my stat window

These values are then used below:

  • Step 3 = 870 + (1504 / 10)
  • Step 4 = 1808 + 150
  • Step 4 = 2828

Post Cap AC Calculations

This section will check first if my AC SUM is greater than my total Soft Cap of 2828, compute my Post Cap AC, and then do it’s thing to compute the final Mitigation AC value.

  • My AC SUM was previously computed: 24,922
  • And my Soft Cap Multiplier is 0.33 – found from the ACMitigation.txt file

If 24,922 > 2828: TRUE

  • Step 5 = 24,922 – 2828
  • Step 6 = 2828 + (22,094 * 0.33)
  • Step 7 = truncate(10,119.02)
  • ‘Mitigation AC’ = Step 7

Finally, I have my Mitigation AC number which is the same as my Displayed Mitigation AC number: Mitigation AC = 10,119

Testing: Evasion AC

We’ll use also my level 120 Shadow Knight to test her Displayed Evasion AC value of: 3861

Displayed Evasion AC: Step 1

Open the skills window and find the Defense Skill value.

My SK’s Defense Skill is 450 as shown.

  • Step 1 = (‘Defense Skill’ * 400) / 225
  • Step 1 = (450 * 400) / 225
  • Step 1 = 800

Displayed Evasion AC: Step 2

This step (and it’s sub-steps) will utilize AGI and hAGI values found in the Stat window.

My SK has AGI capped at 1050 and Heroic Agility is 1722. These values will be used.

  • ‘Functional Agility’ = AGI + hAGI
  • ‘Functional Agility’ = 1015 + 1722
  • ‘Functional Agility’ = 2737

The ‘Agility Bonus’ will be computed next, and then we can finish off Step 2 with it:

  • AB Step 1 = [8000 * (‘Functional Agility’ – 40)] / 36000
  • AB Step 1 = [8000 * (2737 – 40)] / 36000
  • AB Step 1 = 599
  • AB Step 2 = (‘Heroic Agility’ / 10)
  • AB Step 2 = 1722 / 10
  • AB Step 2 = 172
  • ‘Agility Bonus’ = AB Step 1 + AB Step 2
  • ‘Agility Bonus’ = 599 + 172
  • ‘Agility Bonus’ = 771
  • Step 2 = Step 1 + ‘Agility Bonus’
  • Step 2 = 800 + 771
  • Step 2 = 1571

Displayed Evasion AC: Step 3

This is an easy step. All we need to do is look in the stat window for mod2 avoidance.

Under “Heroic Mods” of the stat window, my SK’s Avoidance (aka Item Avoidance) is 174.

  • Step 3 = Step 2 + ‘Item Avoidance’
  • Step 3 = 1571 + 174
  • Step 3 = 1745

Displayed Evasion AC: Step 4

My SK is NOT drunk! But it’s helpful to understand how the math gets calculated here:

  • ‘Drunk Value’ = ‘How Drunk’ / 2
  • ‘Drunk Value’ = 0 / 2
  • ‘Drunk Value’ = 0
  • ‘Drunkenness Reduction’ = (110 – ‘Drunk Value’) / 100.0
  • ‘Drunkenness Reduction’ = (110 – 0) / 100.0
  • ‘Drunkenness Reduction’ = 0
  • If ‘Drunkenness Reduction’ > 1.0: ‘Drunkenness Reduction’ = 1.0
  • Since i’m not drunk: ‘Drunkenness Reduction’ = 1.0
  • Step 4 = truncate(Step 3 * 1.0)
  • Step 4 = truncate(1745 * 1.0)
  • Step 4 = truncate(1745.0)
  • Step 4 = 1745

Displayed Evasion AC: Step 5

This is another easy step. It was previously discussed that all players, regardless of level have an innate evasion AC of 10 points. This will simply get added to the previous step:

  • Step 5 = Step 4 + 10
  • Step 5 = 1745 + 10
  • Step 5 = 1755

Displayed Evasion AC: Step 6

Passive melee avoidance from AAs will get calculated here. My SK has:

  • Combat Agility (CA) – Rank 87: Increases avoidance by 105%
  • Physical Enhancement (PE) – Rank 15: Increases avoidance by 15%

We’ll compute my SK’s ‘AA Avoidance” by turning the percentages into a working number that will include decimals:

  • ‘AA Avoidance’ = (100 + CA + PE) / 100
  • ‘AA Avoidance’ = (100 + 105 + 15) / 100
  • ‘AA Avoidance’ = (220) / 100
  • ‘AA Avoidance’ = 2.2

Lastly, we can work my SK’s ‘AA Avoidance’ into the final step:

  • Step 6 = truncate(Step 5 * ‘AA Avoidance’)
  • Step 6 = truncate(1755 * 2.2)
  • Step 6 = truncate(3861)
  • Step 6 = 3861

Computed Defense = Displayed Evasion AC

Not too bad, right? Completing the last step gave us the exact same Displayed Evasion AC value of 3861 that my SK sees in her inventory window.