DrDamage
In-game theorycraft. Calculates actual damage/healing based on gear, talents and buffs.
Mists of Pandaria 
The Burning Crusade 
Wrath of the Lich King Addon Details
Expansion
Developers
Having issues?
DrDamage displays the calculated, average damage or healing of abilities with talents, gear and buffs included on your actionbar buttons. The addon will also add various information to the default tooltips in your spellbook and on the actionbar.
Download DrDamage
Cataclysm
4.3.4More addons for Cataclysm
Discover other addons that might interest you
Quest-o-matic
Auto accepting and turning in quests
TellMeWhen
Notifications about cooldowns, buffs, etc.
DiminishingReturns
Helps tracking your teammate and own diminishing returns on hostile players
WarlockReminder
Provides helpful buff reminders for Warlocks.
Target Nameplate Indicator
Puts a texture on your target's nameplate to make them stand out. Configure by editing…
Icetip
Icetip
Better Health Numbers
This addon will add percentages and health numbers to the default unit frames.
Comix
Comix plays funny sounds and pictures depending on the situation.