Damage/Weapon Damage

Weapon Damage is the first damage value shown on the top of the weapon's tooltip in game.

It's calculated by the Gear Score-Based Damage multiplied by the sum of the Level and Attributes modifiers:

$$ { \begin{aligned} \text{Weapon Damage} &= {\color{RawSienna}{\text{Gear Score-Based Damage}}} \times (1 + {\color{RawSienna}{\text{Level Mod}}} + {\color{RawSienna}{\text{Attributes Mod}}}) \end{aligned} } $$

Gear Score-Based Damage
Gear Score-Based Damage is the lower Damage entry shown on the tooltips of all weapons. It also shows the Damage Type (,, etc) next to the number.

The game calculates the initial value based on the Base Damage of the weapon type (Musket, Fire Staff, etc) and then applies a compound interest formula taking the Gear Score (GS) of the weapon into account.

$$ { \text{GS-Based Damage} = \begin{cases} {\color{RawSienna}{\text{Base Damage}}} \times {\bigg(1 + 0.0112 \bigg)^{\left\lfloor{\frac{ {\color{RawSienna}{\text{GS}}} - 100}{5}}\right\rfloor}} & \text{if } 100 \leq {\color{RawSienna}{\text{GS}}} \leq 500 \\ {\color{RawSienna}{\text{Base Damage}}} \times \bigg(1 + 0.0112 \bigg)^{80} \times \bigg(1 + 0.6667 \times 0.0112 \bigg)^{\left\lfloor{\frac{{\color{RawSienna}{\text{GS}}} - 500}{5}}\right\rfloor} & \text{if } {\color{RawSienna}{\text{GS}}} > 500 \end{cases} } $$