Math Reference: Crit Damage Calculations
January 11, 2016 Leave a comment
Before I answer this question, I’ll cover how crit damage bonuses work, and how multiple sources interact.
With the introduction of additional sources of Crit Damage in Legion via Artifact Traits there seems to be a mixture of how these effects are applied: Bonus and “Extra Bonus” types.
( ( Base Critical Damage * (1 + Bonus 1) * (1 + Bonus 2) ) – 1 ) * ( 1 + Extra Bonus effect 1 ) * ( 1 + Extra Bonus effect 2 ) + 1 = Total Critical Strike Damage
Bonus Critical Damage applies within the first part of the equation, increasing the damage of a critical by multiplying the whole spell. Extra Bonus Critical Damage applies only to the Critical Damage portion of the spell.
Bonus and Extra Bonus types can be identified by looking for Misc Value 15 (Extra Bonus) or Misc Value 126 (Bonus, although some Misc Value 4’s are also Bonus values) in spell data. You can see this by running the following command in a Command Prompt (cmd.exe in Windows):
This will return:
As you can see, Molten Blast has a Misc Value of 15, which means that it’s an Extra Bonus, and that the tooltip is halved so that it gives a rough estimate of the Bonus equivalent (ie: a 2% Bonus is equal to a 4% Extra Bonus when there aren’t multiple multipliers).