Damage calculation
This page describes the mechanics of damage calculation, and may be particularly useful for players who want to spade out values for various effects related to damage. This is important for skill coefficients and other values which may not be documented ingame.
Skill damage[edit]
Weapon skill[edit]
Damage = (Weapon strength * Power * Skill coefficient) / Armor
 Weapon strength: A uniformly distributed random number taken from within the range listed as "Weapon Strength" on the equipped weapon. The weapon damage used for a skill will typically be that of the weapon associated with that skill; utility and elite skills are typically not affected by weapon damage and use a range based on the player's level.
 Power: The current power as listed on the Hero tab.
 Skill coefficient: Every skill has a damage coefficient used to calculate damage inflicted.
 Armor: The target's current armor as listed on the Hero tab. Armor is the sum of defense and toughness.
Power[edit]
Power is the primary attribute for calculating how much damage is dealt. Power can be increased through equipment, the might boon, and various effects that provide bonuses to power, such as consumables. The base power attribute for a level 80 character is 1000.
Weapon strength[edit]
Weapon strength is a factor of damage calculation for weapon skills. The weapon strength on each weapon is given as a range of values and is affected by the type, level, and rarity of the weapon. Whenever a weapon skill deals damage, a value is chosen at random from the range of weapon strength on the equipped weapon. When a damage value is displayed in skill tooltips, the midpoint of the range is used to calculate the displayed value.
 Values for ascended weapons
Weapon  Weapon strength  Midpoint 

Main hand  
Axe  900  1100  1000 
Dagger  970  1030  1000 
Mace  940  1060  1000 
Pistol  920  1080  1000 
Scepter  940  1060  1000 
Sword  950  1050  1000 
Offhand  
Focus  873  927  900 
Shield  846  954  900 
Torch  828  972  900 
Warhorn  855  945  900 
Twohanded  
Greatsword  1045  1155  1100 
Hammer  1034  1166  1100 
Longbow  966  1134  1050 
Rifle  1035  1265  1150 
Shortbow  950  1050  1000 
Staff  1034  1166  1100 
Aquatic  
Harpoon gun  950  1050  1000 
Spear  950  1050  1000 
Trident  950  1050  1000 
Other sources for weapon strength values[edit]
The values above apply to weapon skills, other types of skills may use different weapon strengths:
 Profession mechanics such as Engineer's tool belt skills will typically use the currently equipped mainhand weapon in calculations.
 Transforms such as Death Shroud have their own unique weapon strengths, that can vary between game modes. Tooltips for transform skills are frequently incorrect, making the true weapon strength difficult to verify.
 Kits and conjures use a standardised weapon strength that is dependent on the equipped mainhand weapon's rarity. In PvE, exotic weapons yield a midpoint of 922.5 and ascended weapons yield a midpoint of 968.5.
 Utility skills, and skills triggered by traits or runes/sigils use a base weapon strength with a midpoint of 690.5 and a variance of 35.
In addition, entities spawned by skills such as turrets, minions or illusions have their own weapon strength and may or may not scale with the player's own stats.
Armor[edit]
Armor is calculated as the sum of the toughness attribute and the defense value. The defense rating is the sum of all the defense values provided by armor and any equipped shield. Trinket slots do not provide defense, although they can provide a bonus to toughness. The profession determines whether the player can wear heavy, medium, or light armor, where heavy armor provides the most defense and light armor provides the least defense.
 Defense values for ascended armor
Armor piece  Light  Medium  Heavy 

Helmet  77  102  127 
Shoulders  77  102  127 
Chest  330  355  381 
Gauntlets  140  165  191 
Leggings  203  229  254 
Boots  140  165  191 
Total  967  1118  1271 
Condition damage[edit]
Condition damage is displayed in the skill tooltip. The value is handled in {{skill fact}} and does not require users to enter the values manually. The values below are valid in PvE:
Condition  Stacking  Formula 

Bleeding  Intensity  0.06 * Condition Damage + 0.25 * Level + 2

Burning  Intensity  0.155 * Condition Damage + 1.55 * Level + 7

Poisoned  Intensity  0.06 * Condition Damage + 0.375 * Level + 3.5

Confusion  Intensity On Skill Use 
0.1 * Level + 2 0.195 * Condition Damage + 1.15 * Level + 3.5

Torment  Intensity While Not Moving 
0.06 * Condition Damage + 0.25 * Level + 2 0.09 * Condition Damage + 0.36 * Level + 3

Damage calculation[edit]
The formula for damage inflicted on a target can be generalized to damage modifiers that increase the amount of damage inflicted or decrease the amount of damage received.
Damage = (Skill damage * Positive multipliers) / (Armor * Negative multipliers)
The majority of damage multipliers combine in a multiplicative fashion rather than additive; i.e. they stack on top of each other instead of being calculated separately. However, some sigils, traits, and effects from utility skills stack additively with each other. For example, a Superior Sigil of Force (5%), a slaying Sigil (3%), an additive 10% trait, a multiplicative 20% trait and the (6) bonus of the Superior Rune of the Scholar (5%) combine for a final damage bonus of (1 + 0.05 + 0.03 + 0.1) * 1.2 * 1.05 = 1.4868
or approximately 48.7%.
Examples of positive multiplier[edit]
 Critical hit: 150% +1% for each 15 points in Ferocity.
 Vulnerability: +1% per stack of vulnerability, up to 25% total.
 Potion of Slaying: +3..10% against specific family.
 Superior Sigil of Force: +5% damage.
 Relic of Fireworks: +7% damage after using a weapon skill with a recharge time of 20 seconds or more.
Examples of negative multiplier[edit]
 Glancing blow: 50% from weakness, 50% chance of triggering
 Protection: 33% damage
Testing[edit]
Damage coefficient[edit]
In an ideal world skill tooltips will match the damage a skill actually deals, but there are multiple instances where this is not the case. You may therefore wish to calculate skill coefficients yourself using the damage equation. We have many variables, but fortunately there are tools for getting constant values. Players can test skills in the Heart of the Mists area for PvP, or the Special Forces Training Area for PvE.
In PvP the power value can be fixed by unequipping all equipment that provides attribute bonuses. The power for a level 80 player with no equipment is 1000. The weapon strength values are given by the weapon type that is equipped and are equivalent to a level 78 exotic weapon found in PvE. The armor value of the foe we are using the skill on is needed. Fortunately, the testing dummies in Hall of Memories are suitable punching bags, but we need to know how much armor they have.
Golem  Armor 

Target Golem  Heavy  2597 
Target Golem  Medium  2322 
Target Golem  Light  2185 
The Golem in the Special Forces Training Area also has an armor value of 2597.
We will use the heavy golem for our calculations, as tooltips assume this value for their calculations. Before testing we need to make sure no positive or negative multipliers are in effect (or be aware of those that are). You may want to attempt to minimise your crit chance as tooltips assume the attack is not a critical hit.
We can now use the equation to calculate the skill coefficient based on the damage inflicted by the weapon skill based on the type of weapon. Our formula will look like:
Damage = Weapon strength * power * Skill coefficient / 2597
We can then solve the equation for the skill coefficient given the damage, after looking up the weapon strength of the weapon type:
Skill coefficient = 2597 * Damage / (Weapon strength * power)
By comparing the damage you deal against the minimum and maximum values for the weapon strength, you can verify whether or not the tooltip gives the correct information.
Glossary[edit]
 Skill  An attack or action that inflicts one or more effects.
 Effect  A mechanic that modifies the state of a player or NPC.
 Damage  Any effect from a skill that reduces the amount of health of a target.
 Weapon  A piece of equipment that gives access to weapon skills.
 Damage range  The range of damage on a weapon. The damage is equally distributed random function between a minimum and maximum damage value.
 Weapon strength  The average damage inflicted by a weapon; the average value of the minimum and maximum damage.
 Power  An attribute that increases the amount of direct damage inflicted by an effect.
 Armor (attribute)  An attribute calculated as the sum of defense and toughness
 Defense (attribute)  The sum of defense rating for all pieces of armor equipped.
 Toughness  An attribute that decreases the amount of direct damage received by an effect.