Damage calculation

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This page describes guidelines for users 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 in-game.

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 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 level 80 exotic weapons
Weapon Weapon strength Midpoint
Main hand
Axe 857-1048 952.5
Dagger 924-981 952.5
Mace 895-1,010 952.5
Pistol 876–1,029 952.5
Scepter 895–1,010 952.5
Sword 905–1,000 952.5
Focus 832–883 857.5
Shield 806–909 857.5
Torch 789–926 857.5
Warhorn 814–900 857
Greatsword 995–1,100 1047.5
Hammer 985–1,111 1048
Longbow 920-1080 1000
Rifle 986-1,205 1095.5
Shortbow 905–1,000 952.5
Staff 985–1,111 1048
Harpoon gun 905–1,000 952.5
Spear 905–1,000 952.5
Trident 905–1,000 952.5

Other sources for weapon strength values[edit]

Most sources of damage scale linearly with power, except for skills used by minions, pets, or other NPC companions. These sources include:

  • Utility skills
  • Elite skills
  • Profession mechanics


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 level 80 exotic armor
Armor piece Light Medium Heavy
Helmet 73 97 121
Shoulders 73 97 121
Chest 314 338 363
Gauntlets 133 157 182
Leggings 194 218 242
Boots 133 157 182
Total 920 1064 1211

This translates to light armor professions taking 15% more damage than heavy armor professions, assuming toughness is constant.

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.

Condition Stacking Formula
Bleeding.png Bleeding Intensity 0.06 * Condition Damage + 0.25 * Level + 2
Burning.png Burning Intensity 0.155 * Condition Damage + 4.0 * Level + 8
Poison.png Poison Intensity 0.06 * Condition Damage + 0.375 * Level + 3.5
Confusion.png Confusion Intensity. 0.0375 * Condition Damage + 0.421875 * Level + 3.75
0.06 * Condition Damage + 0.25 * Level + 2
Torment.png Torment Intensity 0.06 * Condition Damage + 0.25 * Level + 2

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)

Damage multipliers combine in a multiplicative fashion rather than additive; i.e. they stack on top of each other instead of being calculated separately. For example, the Superior Sigil of Force (5%), Superior Sigil of the Night (10%), a 10% trait, a 20% trait and the (6) bonus of the Superior Rune of the Scholar (10%) combine for a final damage bonus of 1.05 * 1.1 * 1.1 * 1.2 * 1.1 ≈ 1.677 or approximately 67.7%.

Positive multiplier[edit]

Negative multiplier[edit]

  • Glancing blow: -50% from weakness, 50% chance of triggering
  • Protection: -33% damage
  • Potion of Slaying: -10% against specific family


Damage coefficient[edit]

The skill coefficient for weapon skills can be calculated using the damage equation. We have many variables, but fortunately there are tools for getting constant values, and a place every player can test skills is the Heart of the Mists area. 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

We will use the heavy golem for our calculations. Before testing we need to make sure no positive or negative multipliers are in effect. 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 * 1000 * Skill coefficient / 2597

We can then solve the equation for the skill coefficient given the damage, after looking up the average weapon strength of the weapon type.


  • 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.
    • Direct damage - A skill effect that reduces the amount of health of the target.
    • Condition damage - Damage inflicted by a condition, measured by damage per second over a period of time.
    • Fall damage - Damage inflicted from a fall, damage inflicted scales with distance fallen and measured as a percentage of maximum health.
  • 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.