Critical hit

Critical hits occur randomly when striking enemies. By default, each successful hit on an enemy has a 4% chance of being a "critical hit", dealing approximately double the usual damage of the weapon in use with 40% more knockback. A small number of weapons have a base critical strike chance that is higher than the 4% default. In addition, certain modifiers, armor bonuses, accessories, and buffs can boost the player's effective critical strike chance.

Visually, critical hits display as slightly exaggerated bold damage numbers that linger on-screen for a longer period than damage numbers from ordinary hits.

Note that minions, and players attacking other players in PvP, cannot currently deal critical hits.

Maximizing critical hits

 * Maximal Melee Crit chance is 121% by combining Dragon Mask, Frost Breastplate, Chlorophyte Greaves, Godly/Demonic/Zealous Obsidian Swordfish, Lucky Eye of the Golem, Lucky Destroyer Emblem, Lucky Celestial Stone, Lucky Moon Stone, Lucky Moon Charm while under influence of Rage Potion, Bowl of Soup and Ale. As this chance caps at 100%, you can skip minor items like Celestial Stone (-2), Moon Stone (-2), Moon Charm (-2) or switch to Chlorophyte Armor (-8) and still have 100% chance. Also, you can switch the Dragon Mask or the Hallowed Mask and still have 116% chance.
 * Maximal Ranged Crit chance is 124% by combining Orichalcum Helmet, Shroomite Breastplate, Chlorophyte Greaves, Unreal Sniper Rifle, Lucky Eye of the Golem, Lucky Sniper Scope, Lucky Destroyer Emblem, Lucky Celestial Stone, Lucky Moon Stone while under influence of Rage Potion and Bowl of Soup. As this chance caps at 100%, you can skip minor items like Celestial Stone (-2), Moon Stone (-2) and switch to full Shroomite Armor (-10) and still have 100% chance. It is even possible to use different weapon (-15) as the stealth effect from armor will add extra 10% back when needed.
 * Maximal Magic Crit chance is 94% by combining Orichalcum Headgear, Spectre Robe, Chlorophyte Greaves, any Mythical weapon, Lucky Eye of the Golem, Lucky Destroyer Emblem, Lucky Celestial Stone, Lucky Moon Stone, any Lucky accessory while under influence of Rage Potion, Bowl of Soup and Crystal Ball. Spectre Robe can be also replaced by Hallowed Plate Mail or Chlorophyte Plate Mail. (Also, if last acessory will be Lucky Sniper Scope, you will have totally 104% of critical strike chance).

History
Coup Critique