# Skull Grasp damage calculation?

Skull Grasp "Increase the damage of Whirlwind by 300–400% weapon damage."

The Wastes set has "Whirlwind gains the effect of the Dust Devils rune and Dust Devils damage is increased to 2500% weapon damage."

Helm and Boots can have "Increase Whirlwind Damage by 15%." for a total skill damage multiplier of 1.3

Whirlwind naturally does "340% weapon damage."

Without skull grasp, the calculation seems to be:

Whirlwind: 340% * 1.3 = 442%

Dust Devil: 2500% * 1.3 = 3250%

How does Skull Grasp factor in?

The most prevalent answer I've found is that it factors into both WW and DD additively:

Whirlwind: (340%+400%) * 1.3 = 962%

Dust Devil: (2500%+400%) * 1.3 = 3770%

But I've also seen reports that it doesn't affect DD damage at all. Can anyone confirm?

So you have to read the text for its literal interpretation.

Whirlwind "does 340% weapon damage".

So let's say you have 2k weapon damage = 680,000 is now 100% of the damage that whirlwind does.

Damage that whirlwind does (Whilrwind by X damage) =/= whirlwind weapon damage (Whirlwind by X weapon damage). So this calculation is correct Whirlwind: (340%+400%) * 1.3 = 962%

Also, Skull Grasp does not effect Dust Devils as Dust Devils are their own attack, with it's own weapon damage calculation, and Skull Grasp only effects Whirlwind. (Considering the fact that Dust Devils are coming from a Whirlwind, I understand your instinct to think they are connect, but suppose Blizz added a new set that generates Dust Devils simply from walking, you would not expect Skull Grasp to have effect.)

• First, if you argue that Dust Devils are not Whirlwind, then do you agree that +% Whirlwind damage does affect Dust Devils? And if it does, does that defeat your logic? Second, do you have any evidence from testing? Commented Aug 26, 2015 at 5:51
• @OrcJMR No i don't agree that % whilrwind damage effects the damage done by Dust Devils. perhaps i can try to find the necessary items to test this, but I strongly thing it works this way due to other mechanics like tal rasha meteors which are effected by % meteor despite being triggered by other spells. An actual test to confirm would be definitive though. also one more comparison, sweeping wind cyclone for monks, the tornadoes don't rise in DPS with + % sweeping wind damage, I can test this one tonight to confirm. Commented Aug 26, 2015 at 20:46
• Okay, but lots of people around different forums don't agree with you. Here's one thread, and there is a host of hits in Google on "does whirlwind damage [affect / effect / work on / increase] dust devils" Commented Aug 27, 2015 at 5:13
• Yeah, % whirlwind damage on helm/boots definitely effects WW damage. Commented Aug 27, 2015 at 18:11