Useful for all types of tanks, though two will have 0% block.
Displays something like "5% miss + 12.55% dodge + 13.75% parry + 52.65% block = 83.95% total" in the chat log.
Code:
/script local function f(v)return math.floor(100*v)/100 end;local d=f(GetDodgeChance());local p=f(GetParryChance());local b=f(GetBlockChance());print("5% miss + "..d.."% dodge + "..p.."% parry + "..b.."% block = "..(5+d+p+b).."% total")
Note that Kings/MotW will give about 0.2% parry, and strength buff (DK Horn of Winter, Shaman Strength of Earth, Warrior Battle Shout) will give about 0.6% parry (about - varies depending on your parry % because of diminishing returns); the macro will display your current combat table values including all buffs, complete with weapon and other procs.
If you're using a stacking avoidance trinket (such as the Spine encounter dodge or agi stackers), let them stack up before considering what your "typical in-combat CTC" is; during most combat those trinket stacks will not fall off so you can consider them to have static value.
Well-fed 90 mastery food (lavascale minestrone) will give warriors 0.75% block, paladins 1.125%.
Well-fed 90 strength food will give warriors, paladins and DKs about 0.1% parry (approximately, with typical diminishing returns).