Defense macro (tanks)

this macro will automatically calculate your defense rating and resilience rating into one solid number determining if you meet the 5.6% crit reduction needed to be crit-proof.

Druids with 3/3 Survival of the Fittest
/script DEFAULT_CHAT_FRAME:AddMessage(2.6-(GetCombatRatingBonus(CR_DEFENSE_SKILL)*.04+GetCombatRatingBonus(CR_CRIT_TAKEN_MELEE) ),1,0.5,0)

Paladins and Warriors with 5/5 Anticipation
/script DEFAULT_CHAT_FRAME:AddMessage(4.8-(GetCombatRatingBonus(CR_DEFENSE_SKILL)*.04+GetCombatRatingBonus(CR_CRIT_TAKEN_MELEE) ),1,0.5,0)

Druids, Warriors and Paladins without any of the previously mentioned talents.
/script DEFAULT_CHAT_FRAME:AddMessage(5.6-(GetCombatRatingBonus(CR_DEFENSE_SKILL)*.04+GetCombatRatingBonus(CR_CRIT_TAKEN_MELEE) ),1,0.5,0)

When you run that macro, if the number it gives you is negative (examle -0.415626267) that means you have more than enough crit reduction, in fact you have 0.415626267% more crit reduction than needed. If the number positive, then you need that percentage more crit reduction to be crit-immune.

Enjoy ^_^