Critical strike is a passive ability that gives a chance to deal bonus damage on a successful attack.
Mechanics
A Critical Strike's occurence is determined upon beginning an attack, and not upon attack launch or attack landing. This means when, for example, having a Crystalys and starting an attack, but then upgrading the Crystalys into a Daedalus, the attack still applies the Crystalys crit, since it was determined upon attack begin. Or when attacking an enemy affected by Soul Rend, and the debuff expires during an already started attack's animation, that attack still applies the crit, since it started while the debuff was still there.
Multiplier
An attack which triggers Critical Strike has its total damage value multiplied by the given multiplier of the source of the Critical Strike. This means a critical strike is basically an attack damage amplifier, as it does not add extra damage on top of the attack damage, but directly increases the damage of the attack by multiplying it.
The multiplier is applied before any reductions or amplifications on the target or on the attacking unit. It only counts the unit's main attack damage (base damage, plus damage gained from the primary attribute), plus any bonus damage (percentage and flat bonuses) it has, meaning any damage instance added to the attack damage which is separete from the attack damage itself is not considered by critical strikes. If an ability adds its damage directly to the attack damage, then it may be considered by Critical Strike, though there are exceptions to this. See Final Attack Damage for the complete calculation.
All chance-based sources of Critical Strike use pseudo-random distribution.
Visual feedback
When a Critical Strike occurs, a red-colored number pops up on the victim of the strike, with a lightning bolt icon on the right side of the number. This number shows the multiplied damage value before any reductions or amplifications. This means the displayed value does not equal the damage the target actually took from the attack.
Stacking
When having multiple sources of Critical Strike, and both trigger on the same attack, the Critical Strike with the higher multiplier takes priority, while the lower one does nothing. This means their proc chances stack, working independently from each other, but their effects do not stack, resulting in a diminishing behavior.
Attack modifier interactions
Critical Strike is an attack modifier which fully stacks with any other modifier. However, it does not interfere with any attack modifier. If an attack modifier increases or reduces attack damage, it is counted by the critical damage multiplier. Abilities which grant conditional attack damage bonuses may or may not be by the multiplier.
- Lifesteal: Lifesteal is calculated after critical strikes, which means that it increases the amount of life you steal.
- Cleave: Cleave is calculated after critical strikes, which means it deals increased damage to all units within the cleave radius.
Conditional attack damage bonuses which are counted by critical strike are:
Conditional attack damage bonuses which are not counted by critical strike are:
- Abyssal Blade – Bash
- Anti-Mage – Mana Break
- Diffusal Blade – Manabreak
- Faceless Void – Time Lock
- Javelin – Pierce
- Lua error: Found no Cargo data for "Mirana - Mana Break".
- Monkey King Bar – Pierce
- Necronomicon Warrior – Mana Break
- Roshan – Bash
- Shadow Blade – Shadow Walk
- Silver Edge – Shadow Walk
- Skull Basher – Bash
- Slardar – Bash of the Deep
- Sniper – Headshot
- Troll Warlord – Berserker's Rage
- Lua error: Found no Cargo data for "Ursa - Fury Swipes".
- Lua error: Found no Cargo data for "Weaver - Mana Break".
Sources of chance-based critical strike
- Proc Chance: 20%
Critical Damage: 200%
Average DPS Increase: 20% - Proc Chance: 20%
Critical Damage: 175%
Average DPS Increase: 15% - Proc Chance: 30%
Critical Damage: 225%
Average DPS Increase: 37.5% - Proc Chance: 20%/25%/30%/35%
Critical Damage: 180%
Average DPS Increase: 16%/20%/24%/28% - Proc Chance: 40%
Critical Damage: 150%/175%/200%
Average DPS Increase: 20%/30%/40%
Affects all units under Lycan's control during Shapeshift. - Proc Chance: 30%
Critical Damage: 200%
Average DPS Increase: 30% - Proc Chance: 9%/11%/13%/15%
Critical Damage: 300%
Average DPS Increase: 18%/22%/26%/30%
Works against wards.
Other sources
The following abilities involve a critical strike mechanic, although they are not triggered as a chance on attack.
- Critical Damage: 5
Causes all attacks against the targeted enemy to be critical strikes. - Critical Damage: 140%/170%/200%
Causes all attacks of Bounty Hunter against the tracked enemy to be critical strikes. - Critical Damage: 130%
Cooldown: 7
Attacks with a guaranteed critical strike when off cooldown.This is an old ability.