Tuesday, March 31, 2009

Chance to Crit vs Multiple Mobs

Assuming we never miss, and are never blocked, parried, or dodged, how often will we be able to proc Savage Defense while using Swipe versus multiple mobs?

To find our chance to crit on a Swipe during a trash tanking scenario versus numerous mobs, we need to understand how the combined probability of our base crit chance stacks up.

Put another way, a 33% chance to critical strike on an attack doesn't yield a 99% chance to critical strike when attacking 3 mobs simultaneously. The actual number is closer to 69.92%, because of how combined probability works.

The formula for calculating crit chance versus multiple mobs is actually the following recurrence relation:

crit chance vs multiple mobs

Where n = number of mobs, and c = chance to crit versus one mob.

This formula yields the following values for a range of base critical strike chance:

See also: spreadsheet for critical strike chance versus multiple mobs.


  1. Thats awesome I love it! Its really cool to find a smart blogger who gives us some math & numbers, but leaves the conclusions up to us.

  2. excelent post. however it look a little better if you includ maul into the equation. Then you will get 5 hits on 3 mobs = 83% chance for a crit.
    with added haste we might even attack faster than the mobs, giving us even better chance.

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