Calculating Mod Bonuses

When modding a weapon, the order in which bonuses are applied follows a consistent pattern. When combining different kinds of damage, bonuses, the following rules apply:

Mods of the same Type
All mods that add a bonus of the same type have their bonus added together. For example, if a weapon has Serration giving +165% damage and Heavy Caliber also giving +165% damage, it will receive a total of +330% damage.

This is true of all bonuses, not just damage. Combining Speed Trigger (+60% Fire Rate) and Shred (+30% Fire Rate, +1.2 Punchthrough) will give a total of +90% Fire Rate.

Damage Types
Mods primarily increase damage in one of four different ways:


 * 1) Some mods increase the base damage of the weapon. This is usually written as simply "+X% damage". For example, see Hornet Strike and Serration
 * 2) Some mods increase physical damage types., , and are the physical damage types. For example, see Fanged Fusillade or Piercing Caliber.
 * 3) Some mods increase primary elemental damage types., , , and are the primary elemental damage types. For example, see Pathogen Rounds or Hellfire.
 * 4) Some mods increase damage against enemies of a certain faction. For example, see Bane of Corpus or Bane of Infested

The Damage Application Order
When calculating damage, first base damage bonuses are added together and applied. For example, the Karak has a base damage of 27. Equipping a max rank Serration (+165% base damage) adds 1.65 * 27 = 44.55 additional damage for a total of 71.55 damage. The added damage will be of the same type(s) the weapon innately deals.

Then, all elemental and physical damage bonuses are calculated based on the modified base damage. For example, adding a Hellfire (+90% damage) to a Karak that already has Serration equipped will add 90% of 71.55 for a total of 64.4  damage. This damage is added to the base, and the Karak now deals a total of 135.95 damage if you add together all damage types.

After that, faction damage bonuses are applied to all damage types. A Karak equipped with Serration, Hellfire, and Bane of Corpus (+30% damage against Corpus) will deal an extra .3 * 71.55 = 21.47 physical damage and an extra .3 * 64.4 = 19.32 damage for a total of 176.74 damage of all types.

For weapons that fire multiple projectiles like Shotguns or Cernos Prime, this damage is split evenly across all projectiles to get the base damage per projectile. If the weapon only fires one projectile at a time, all of the damage is the base damage per projectile.

If the weapon has Multishot from a mod like Split Chamber, it will fire additional projectiles, each of which will deal the base damage per projectile. For weapons that only fire a single projectile, Split Chamber's 90% multishot will cause each shot to randomly have a 90% chance to fire two projectiles instead of one. Since Cernos Prime already fires 3 arrows per shot, adding Split Chamber will make it fire 3 * .9 = 2.7 additional arrows, so each shot will fire at least 5 arrows, and 70% of shots will fire 6.

On continuous beam weapons like the Glacion, the damage of the beam simply has the multishot chance added. For example, adding Split Chamber to a Glacion will act as an additional 90% total damage bonus.

Once damage is calculated, it may be affected on impact by Critical Hit mechanics or modified based on the opponent's armor. For detailed calculations of how various damage types affect different types of enemies, see the Damage page.

Calculating Physical Damage
Physical damage mods apply only to base damage of the same type. For example, at max rank Fanged Fusillade increases damage by +120%. The Karak does 27 damage split into 12.15, 8.1 , and 6.75. A Karak equipped a max rank Fanged Fusillade will gain (6.75 * 1.2) = 8.1 additional damage for a total of 14.85  and 35.1 total damage.

If a Physical damage mod is added to a weapon that does no physical damage of the corresponding type, the mod will have no effect. For example, the Amprex does entirely damage when unmodded, so Fanged Fusillade will do absolutely nothing.

Calculating Elemental Damage
Elemental damage mods apply to all damage done by a weapon. For example, a max rank Hellfire adds 90% damage to a rifle. If a Karak was equipped with a max rank Hellfire, it would gain 27 * .9 = 24.3 damage.

Each two different elemental mods will be added up into a Combined Element, with different damage multipliers against certain enemies. For combined elements, the slots are ordered from left to right, top row then bottom row, with any inherent elemental damage (from the weapon) added last. For example, if both Hellfire (+ damage) and Cryo Rounds (+ damage) are equipped on an Amprex, they will combine to add damage to the weapon's base  damage. If only Hellfire is used, it will combine with the Amprex's base damage to make  damage instead.

If multiple mods of the same element are added, only the first is used when making combinations. For example, if Hellfire, Cryo Rounds, and Thermite Rounds are added to an Amprex, no matter what the order is the weapon will deal and  damage since the  element has already combined with, so the second  mod simply increases the amount of  damage dealt.

Combining Physical and Elemental Damage
Both Physical and Elemental damage are combined in the same step and are based only on the weapon's base damage and any mods that effect base damage.

In terms of raw damage, this makes a +90% damage bonus superior to +90%  damage bonus unless the weapon deals all of its damage as. In terms of actual impact, the total effect varies based on the armor type of enemy being damaged.

Total Damage Formula
If you're interested in simply calculating the total damage per shot fired, the equation (ignoring multishot and criticals) is:

Base Damage * (1 + Base Damage Bonus) * (1 + Elemental Damage Bonus + Weighted Physical Bonus) * (1 + Faction Damage Bonus) = Total Damage

Weighted physical damage is the physical bonus multiplied by the percentage of base damage that is made up of the specific physical bonus.