Weapon Damage is a stat that increases Bullet Damage and Melee Damage.

Video explaining Weapon Damage

Base Weapon Properties

Base Bullet Damage

Base Bullet Damage is the amount of damage your Hero deals with no items. This value is unique to each hero and increases automatically as you level up through Boons.

Spreadshots

Spreadshots allow certain weapons to fire multiple bullets at once (such as shotguns or shurikens). In these cases, all calculation rules apply to every individual bullet.

Piercing shots

  Paige's weapon's shots pierce through enemies and can hit multiple enemies per projectile, disappearing only when they hit a map surface. However, they do not deal headshot bonus damage, but can proc headshot items.

  The Doorman's weapon's shots also pierce enemies. Unlike Paige's, they can deal headshot damage but deal half damage to all enemies hit after the first.

Melee damage

Melee Damage scales with Weapon Damage by 50%.

Combat Modifiers

Damage Falloff

Damage Falloff reduces damage based on distance. All heroes have a Falloff Range in which damage is linearly reduced from 100% to 10%.

When aiming at an enemy hero, a dot on their health bar indicates the percentage of damage you will deal:

Dot Color Damage Percentage
Red 10% - 20%
Orange 20% - 35%
Yellow 35% - 75%
Transparent 75% - 100%

Crit Multiplier

Aiming for the head deals increased damage. Troopers, Guardians, and Heroes have a weakpoint hitbox that receives 1.65x bullet damage when hit.

Crit Multiplier=[1+(0.65×Crit Bonus Scale)]×Crit Resist

The following heroes cannot deal critical damage:

Crit Bonus Scale is a stat that modifies critical damage for certain heroes.

Base Crit Bonus Scale Stats
Hero Crit Bonus Scale (%)
 Billy -20
 Celeste -25
 The Doorman -30
 Drifter -45
 Kelvin -25
 Rem -20
 Vyper -30

Target Modifiers

Bullet Resistance

Main article: Damage Resistance

Incoming damage is reduced by the target's Bullet Resist and increased by the attacker's Bullet Resist Reduction. These stats stack multiplicatively. For a detailed breakdown on how multiple items stack, see the main page.

Increased Bullet Damage

Increased Bullet Damage is a debuff inflicted on enemies. It multiplies the total amount of damage they take from you. Because this is applied at the end of the calculation, it also increases the effectiveness of your Flat Weapon Damage.

Flat Weapon Damage

Flat Weapon Damage is an extra amount of damage obtained through certain hero abilities.

Flat Weapon Damage is not increased by your "Weapon Damage %" multiplier. It is an additive source added to your total after the percentage multiplier is applied to your base. However, it is still affected by Damage Falloff, Bullet Resist, and Crit Multipliers.

Weapon Damage Formula

The final damage dealt by a bullet is determined by multiplying your base stats, your item bonuses, and various situational modifiers.

Final Damage=[(Base Damage×Weapon Damage Multiplier)+Flat Bonus]×Falloff×Resistances×Crit Multiplier

Weapon Damage Scaling

Some abilities scale with Weapon Damage.

For most Weapon Damage scaling abilities, they only scale based on the "Bonus Weapon Damage" stat, which is granted by items and Weapon shop investments (see list below). This includes abilities such as   Venator's   Consecrating Grenade,   Gutshot and   Ira Domini.   Paradox's   Kinetic Carbine is an exception, since it scales with her Base Weapon Damage (counting as a full burst shot), and thus increases with Boons. Melee Damage scaling abilities also scale with Weapon Damage, since Melee Damage scales with Weapon Damage (by 50%).

Sources

All weapon items provide an automatic increase in Weapon Damage based on the player's total soul investment in that category:

Souls invested Weapon Damage Increase
 800 +9%
 1,600 +12%
 2,400 +15%
 3,200 +18%
 4,800   +46%
 7,200 +55%
 9,600 +70%
 16,000 +85%
 22,400 +100%
 28,800 +115%

The following items grant increased weapon damage:

This is a dynamic list "Weapon Damage". Edit contents.
Name CostCategoryStat change
  Close Quarters800  Weapon+20% Weapon Damage
  Extended Magazine800  Weapon+8% Weapon Damage
  High-Velocity Rounds800  Weapon+8% Weapon Damage
  Restorative Shot800  Weapon+6% Weapon Damage
  Fleetfoot1,600  Weapon+6% Weapon Damage
  Long Range1,600  Weapon+40% Weapon Damage
  Opening Rounds1,600  Weapon+8% Weapon Damage
  Recharging Rush1,600  Weapon+10% Weapon Damage
  Titanic Magazine1,600  Weapon+14% Weapon Damage
  Cultist Sacrifice3,200  Weapon+10% Weapon Damage
  Escalating Resilience3,200  Weapon+18% Weapon Damage
  Express Shot3,200  Weapon+8% Weapon Damage
  Headhunter3,200  Weapon+5% Weapon Damage
  Hollow Point3,200  Weapon+35% Weapon Damage
  Point Blank3,200  Weapon+50% Weapon Damage
  Sharpshooter3,200  Weapon+10% Weapon Damage
+60% Weapon Damage
  Weighted Shots3,200  Weapon+30% Weapon Damage
  Armor Piercing Rounds6,400  Weapon+8% Weapon Damage
  Glass Cannon6,400  Weapon+80% Weapon Damage
  Battle Vest1,600  Vitality+18% Weapon Damage
  Bullet Lifesteal1,600  Vitality+6% Weapon Damage
  Fury Trance3,200  Vitality+6% Weapon Damage
  Colossus6,400  Vitality+15% Weapon Damage
  Inhibitor6,400  Vitality+10% Weapon Damage
  Leech6,400  Vitality+12% Weapon Damage
  Phantom Strike6,400  Vitality+15% Weapon Damage
  Siphon Bullets6,400  Vitality+15% Weapon Damage
  Vampiric Burst6,400  Vitality+6% Weapon Damage
  Bullet Resist Shredder1,600  Spirit+9% Weapon Damage
  Unstable ConcoctionLegendary  Spirit+150% Weapon Damage
  •   Headshot Booster deals +45 bonus Weapon Damage with headshots.
  •   Monster Rounds increases Weapon Damage against NPCs by +25%.
  •   Berserker increases Weapon Damage by +7% per stack for sustaining damage.
  •   Headhunter additionally deals +75  x4 bonus Weapon Damage with headshots.
  •   Intensifying Magazine increases Weapon Damage to a maximum of 45% after continuously firing.
  •   Opening Rounds increases Weapon Damage by +25% against enemies above 50% health.

References