Critical hit

• A critical hit occurs randomly (with a 1-in-11 chance, subject to certain modifiers) when hitting with a ranged or melee attack. It increases the amount of damage you deal to your opponent. Specifically, it doubles the weapon power component of the damage:

 weapon damage = (a term based on your stats vs. monster's defense)
                 + Main weapon damage × crit × tsfactor            
                 + Offhand weapon damage
                 + bonus melee damage                              
                 + bonus elemental damage

Where

• crit is 1 for a normal hit, and 2 for a critical hit, and
• tsfactor is 1 for a normal attack, 2 for a Thrust-Smack, and 3 for a Lunging Thrust-Smack.
• Weapon damage is (10%-20% of weapon power + 0 to 1), or 1 if barehanded.

• For a comprehensive list of all items that affect the critical hit percentage, see Critical Hit Chance.

Monster Critical Hits

Monsters can critical hit too -- but a monster critical hit doesn't cause you any extra damage; it just succeeds in hitting when it otherwise would have missed. Monster critical hits, like monster fumbles, occur with a 1/22 (4.5%) chance per round. Thus, the total chance of abnormal monster behavior in any given round is 1/11, the same as player critical hits.