Are you Uncrushable?

Here is a great macro that will calculate your avoidance with and without buffs.

/script DEFAULT_CHAT_FRAME:AddMessage(“Need 102.4 combined avoidance. Currently at:”,0.8,0.8,1)
/script DEFAULT_CHAT_FRAME:AddMessage(GetDodgeChance() + GetBlockChance() + GetParryChance() + 5 +(GetCombatRatingBonus (CR_DEFENSE_SKILL)*150/355 + 20) *0.04,1,0.5,0)

It’s very useful when trying to build a gear set when raid tanking. The only thing to note is that in the line:

(GetCombatRating(CR_DEFENSE_SKILL)*150/355 + 20)

The + 20 assumes you have 5/5 Anticipation. If you don’t, you have to change this line to reflect how much defense you are getting from Anticipation (0 – 20).

Credit: Raymond of Nazjatar
Source: Blessing of Kings

UPDATE:
Edit: Changed GetCombatRating call to GetCombatRatingBonus call. Shortens the macro slightly.

Edit: Also, you have to activate Holy Shield before using this to get results with Holy Shield. Otherwise you’ll look 30-35% worse than you really are.