essence bug?

For some reason when I add essence it doesnt give me excatly the amonunt it is saying.
For example blue ess doesnt give me exactly twice my dmg but actually a bit lower than double. Is this a bug or am I just missing something?

 

Yeah, your base damage on the character screen is not the number that the blue ess is modifying.

Most likely you have additional increased damage % modifiers present, such as a torso with increased damage % lines, or the wisdom skill that goes up to 25/25 for increased damage, or rings of death.

This issue has been discussed before, so I'm not going to get into the math.

 

Novadude is exactly correct. To find you "base damage" that the essence is giving you a % of, add up your total "% Damage" from all sources. This does not include % weapon damage on weapons or the % weapon damage from the skill Behemoth, or the % 2H damage you get from the Black Warlord set or the Bellicose set. Then, take your total damage and divide it by (1+total%damage). For example, if you have 4000 damage and you have +60% damage (say 50% from knowledge and 10% from the Darkness set), then you'd get 4000/1.6=2500. That means that if you put on blues, your damage will go up by 100% of 2500, not 100% of 4000. Your total damage with blues would be 6500 damage, not 8000. The same works with the other % based essence. If you added reds, you'd get 300% of 2500 (7500) and your total damage would be 11500, not 16000.

I hope this makes sense, but rest assured, it is not bugged. It has actually been like this for a really long time.