Damage

Character Damage
A Character's damage is the main factor all other damage scales off.

A multiplier is built and added together: This multiplier is added to the character's base damage plus their level's damage resulting in the character's damage.
 * 1) Elite multiplier
 * 2) -5% for each beetlejuice debuff. Presumed to be the flying bugs from Beetle Queen.
 * 3) +100% if the character is the Aurelionite
 * 4) The multiplier from the item Shaped Glass

Damage for Procs
Minimum between the hit damage * damage coefficient, and the hit damage + character damage * (damage coefficient -1)

Critical Strike
All Survivors have a base of 1% critical chance. Upon Critical strike, damage dealt is twice the amount of a normal attack.

One-shot Protection
A single hit taken can not deal more than  damage.

Trivia

 * If you enable Damage Number in Gameplay Settings, the damage will be displayed after rounding to the nearest integer.