Game Calculations and Stacking Caps

Normally, you don't have to worry about mathematical calculations and formulae behind the game when playing Guild Wars. But some effects stack with each other and give diminishing returns, and in such cases, it pays to have a general idea of how stacking works. We'll cover detailed mathematical calculations in this article to better explain the underlying mechanics of different game effects, but we'll make sure to include game tips and call out the important information.

In addition to stacking, certain effects have a "cap." A cap refers to an upper limit placed on the effect. The attack speed cap, for example, is fixed at 33%. Other effects have caps that single skills can override.

Attack Speed Cap

Attack speed is capped at 33% faster.

Example Stacks:
Dwarven Battle Stance (25%) + "I Will Avenge You!" (25%) = 33%
Aggressive Refrain (25%) + Frenzy (33%) = 33%

Game Tip: Nothing increases attack speed beyond 33%. Typically, one attack speed boost on a Skill Bar suffices for most builds. You can also increase attack speed by using attack skills like Protector's Strike or Mystic Sweep that cause your character to swing a weapon faster. Using these skills back-to-back enhances your overall attack speed and frees you to use a Stance for something other than attack speed, such as a movement speed boost.

Blocking and Chance to Miss

Blocking and "chance to miss" have no cap, and they stack with one another. The more skills you use to block attacks, however, the more you will see diminishing returns for the Energy investment. For example, if you already have a 50% chance to block and get another 50%, you have a total of a 75% chance to block, not the additive result of 100%. Here's how it works.

For every hit, if you have two chances to block, your opponent must get through both block chances in order to hit, so the chances are multiplied. Your opponent's total hit chance is:

(1 - first chance to block) x (1 - second chance to block) = y (opponent's total chance to hit)

Therefore:
1 - y = your total chance to block
Put another way: 1- (first block chance x second block chance) = total block chance

Sample calculations:
50% to block and 50% to block:
(1 - 0.5) x (1 - 0.5) = 0.25
1 - 0.25 = 0.75 or 75% total block chance

And for more than 2 effects:
(1 - first chance to block) x (1 - second chance to block) x (1- third chance to block) = y;
1 - y = total chance to block

So for someone standing in a Ward Against Melee (50%) using both Aegis (50%) and Shield of Deflection (75%) the calculation looks like this:

(1 - 0.5) x (1 - 0.5) x (1 - 0.75) = 0.0625
1 - .0625 = 0.9375 or 93.75% total chance

Game Tip: It is impossible to get to 100% block chance, but with enough elements in the equation you might as well have 100%. Even the 90% miss chance from Blindness completely shuts down melee and ranged attackers. If you bring too much blocking ability to a fight, you might neglect counters to other forms of damage. Blocking certainly plays a large role in surviving PvP, but as the calculations show, sometimes multiple sources of blocking don't really add enough payoff. Instead, strive for a balance between melee defense and other counters.

Casting Time Increases

The maximum time a spell's casting time can increase is 150%. All skills that Daze a target increase that target's casting time by 100% for the duration of the Dazed Condition.

Example stacks:
Dazed (100%) + Migraine (100%) = +150%
Arcane Conundrum (100%) + Frustration (50%) = +150%

Skills that increase casting time:
Air of Disenchantment (range of longer Enchantment casting)
Arcane Conundrum (100% longer)
Dazed (100% longer)
Enchanter's Conundrum (100% longer for Enchantments)
Frustration (50% longer)
Holy Veil (100% longer to Hexes targeting that ally)
Migraine (100% longer)
Nature's Renewal (100% longer to Enchantments and Hexes)
Stolen Speed (25% longer)

Skills that cause the Dazed Condition:
Awe
Beguiling Haze
Bestial Mauling
Broadhead Arrow
Concussion Shot
Golden Skull Strike
Headbutt (use with Plague Touch)
Quivering Blade (use with Plague Touch)
Skull Crack
Smoke Trap
Stunning Strike
Temple Strike

Game Tip: If you plan to inflict Dazed on a target with your build, you can add Arcane Conundrum to a single target and reach the 150% cap. Or, you can hit one person with Dazed, and another with Arcane Conundrum. This will give two enemies a +100% increase to their casting times, which is a more efficient use of your skills.

Duration Lengthening

Enchantments, Hexes, Conditions, Shouts, and Chants have no cap on how long they can last. Consequently, anything that extends these effects will stack.

Enchantment lengtheners:
Blessed Aura (Monk skill to lengthen Monk Enchantments)
Extend Enchantments (Dervish)
Weapon modifications

Note that the additional lengths of time are all based on the original duration. So if you use Blessed Aura at +25% with a staff wrapping of Enchanting +20% and cast a 10-second Balthazar's Aura, your total length comes out to 14.5 seconds. The calculation looks like this:

10 seconds original duration x 25% Blessed Aura = 2.5 extra seconds
10 seconds original duration x 20% Staff Wrapping = 2.0 extra seconds
10 + 2.5 + 2.0 = 14.5 total seconds

Condition lengtheners:
Extend Conditions (Mesmer)
Mystic Corruption (Dervish)

Hex lengtheners:
Chilling Winds (Elementalist Water skill to lengthen Water Hexes)
Mantra of Persistence (Mesmer Inspiration skill to lengthen Illusion Hexes)

Shout/Chant lengtheners:
Enduring Harmony (Paragon)
Vocal was Sogolon (Ritualist)

Game Tip: It doesn't always benefit you to extend the duration of certain game effects. For example, when you apply long-lasting Health degeneration Conditions, you can be fairly certain they will get removed before the duration ends. You might, therefore, gain more in the long run by choosing a weapon modifier such as vampiric that raises damage per second instead of one that increases the duration of a degeneration Condition. Other Conditions, such as Crippled, which don't last as long as Health degeneration Conditions, are more likely to expire naturally. Also, snares serve a crucial purpose in controlling enemy position, so increasing the Crippled duration on your enemy can improve your overall strategy.

Healing Penalty

The healing penalty cap is 40% reduction.

Example stacks:
Defile Flesh (33%) + Deep Wound (20%) = 40% cap
Defile Flesh (33%) + Malign Intervention (20%) = 40% cap

Exception:
Lingering Curse causes 50% reduction in healing.

Healing reduction skills:
Deep Wound (20%)
Defile Flesh (33%)
Lingering Curse (50%)
Malign Intervention (20%)
Mark of Death (33%)
Predatory Season (20%)

Game Tip: Note that life stealing does not count as "healing," so any healing reduction does not affect life stealing skills or vampiric weapons. Also, healing reduction penalty only impacts direct healing, not Health regeneration.

Maximum Health Stacks

Whenever maximum Health gets adjusted, it takes from and gives to the bottom of the Health bar. If you have a +200 Health buff active and only have 180 Health left showing on your Health Bar, when that +200 ends you drop to 1 Health (even though you have a deficit of -20 Health). It doesn't actually kill you unless you take damage. On an interesting note, if you get healed for less than your remaining Health deficit, you'll die. Be careful immediately after a Health boost, such as Endure Pain, expires. If you have 1 Health, inform your healers and hope that nobody accidentally kills you with a small heal. After a brief period of time, you'll recover the -20 Health deficit and start regenerating.

Sources of Maximum Health Increase:
Avatar of Melandru
Defy Pain
Demonic Flesh
Empowerment
Endure Pain
Fertile Season
Generous Was Tsungrai
Health Shrine
Signet of Stamina
Symbiosis
Vital Boon
Vital Weapon
Vital Blessing

Sources of Maximum Health Reduction:
Aura of the Lich
Death Penalty
Deep Wound

Game Tip: The effect of maximum Health adjustment makes Deep Wound incredibly powerful on spikes and makes removing it crucial for survival. In any team situation, informing teammates about a Deep Wound over voice chat or by Ctrl-clicking in game may just save your life.

Movement Speed Cap

Movement speed boost is capped at 33% faster.

Example stacks:
Shadow of Haste (15%) + "Charge!" (25%) = 33%
Storm Djinn's Haste (33%) + "Lead the Way!" (25%) = 33%

Skills that increase movement speed beyond 33%:
Burning Speed
Dash

Game Tip: The Assassin skill, Dash, may not seem like much with its mere 3-second speed boost. However, moving 50% faster practically guarantees you can reach a better position, which is especially important in time-sensitive operations like melee spikes. Factor in low recharge and no attribute requirement, and Dash makes an attractive choice for any build.

Movement Speed Reduction

The normal movement speed reduction cap is 50%. Note that holding a bundle item (such as a relic) slows you down and stacks with snares.

There are, however, several single skills that override the movement speed reduction cap:

Binding Chains (90%)
Dolyak Signet (75%)
Icy Shackles (up to 90%)
Iron Mist (90%)
Mind Freeze (90%)
Shadow Prison (66%)
Water Magic Hexes (many of them slow movement by 66%)

Game Tip: Adding the Crippled Condition on top of a Water Magic snare such as Ice Prison does not slow movement any further; it stays at a 66% reduction. However, using multiple snares ensures the target stays slowed longer because the other team must work harder to remove everything and restore movement to normal.

Skill Recharge

Skill recharge is capped at 50% faster.

Some skills, at high enough attribute levels, can reduce recharge time by more than 50%. These are:

Expert's Dexterity
Mantra of Inscriptions
Symbolic Celerity
Symbolic Posture
Ritual Lord

In addition, other abilities can cause a skill to recharge instantly.

Game Tip: When using one of the above skills to recharge skills 50% or more faster, you don't need to use a weapon with a chance to reduce recharge time. Instead, you can use it for something else, such as reducing recharge time for skills in a different attribute line.