Lifesteal

Lifesteal is a mechanic which heals a player by a portion of the damage they deal to an opponent. There are two main types of lifesteal, each with an associated stat: Bullet Lifesteal, which returns a portion of the bullet damage dealt, and Spirit Lifesteal, which returns a portion of the spirit damage dealt. Bullet and Spirit Lifesteal are calculated independently, but use the same formula.

Calculation

While lifesteal is shown as a percentage (like +20%), different sources of lifesteal do not simply add together. Instead, they stack multiplicatively. This means that as you gain more sources of lifesteal, each new item is slightly less effective than the last.

To calculate your final lifesteal, you can use the following formula:

$\text{Total Lifesteal}=1-(1-L_1)\times (1-L_2)\times (1-L_3)\dots$

(Where $L$ is the lifesteal value of each source expressed as a decimal, e.g., 0.20 for 20%).

Example

If you have 22% Bullet Lifesteal from Fury Trance and 30% Bullet Lifesteal from Leech, your lifesteal is calculated as follows:

1. Convert the percentages to decimals: 0.22 and 0.30.
2. Subtract each from 1: (1 - 0.22) = 0.78 and (1 - 0.30) = 0.70.
3. Multiply those results together: 0.78 × 0.70 = 0.546.
4. Subtract that result from 1: 1 - 0.546 = 0.454.
5. Your final Bullet Lifesteal is 45.4%.

Note: The in-game user interface is inconsistent with rounding, so it may display as 45% or 46%.

Lifesteal vs. Creeps

Lifesteal against creeps (non-hero units) is reduced compared to heroes:

• Bullet Lifesteal vs. creeps: 60% effectiveness (e.g., 10% lifesteal becomes 6%).
• Spirit Lifesteal vs. creeps: 40% effectiveness (e.g., 10% lifesteal becomes 4%).

Bullet Lifesteal

Bullet Lifesteal returns a percentage of all outgoing bullet damage to the player as health.

Sources

List of items

Name	Cost	Category	Stat change
Active Reload	1,600	Weapon	+18% Bullet Lifesteal
Bullet Lifesteal	1,600	Vitality	+16% Bullet Lifesteal
Fury Trance	3,200	Vitality	+22% Bullet Lifesteal
Leech	6,400	Vitality	+30% Bullet Lifesteal
Vampiric Burst	6,400	Vitality	+16% Bullet Lifesteal
Vampiric Burst	6,400	Vitality	+80% Bullet Lifesteal

Spirit Lifesteal

Spirit Lifesteal returns a percentage of all outgoing spirit damage to the player as health.

Sources

List of items

Name	Cost	Category	Stat change
Spirit Shredder Bullets	1,600	Weapon	+8% Spirit Lifesteal
Spirit Rend	3,200	Weapon	+8% Spirit Lifesteal
Spiritual Overflow	6,400	Weapon	+15% Spirit Lifesteal
Spirit Lifesteal	1,600	Vitality	+16% Spirit Lifesteal
Infuser	6,400	Vitality	+80% Spirit Lifesteal
Leech	6,400	Vitality	+30% Spirit Lifesteal
Mystic Reverb	6,400	Spirit	+15% Spirit Lifesteal

Soul Shredder Bullets

The debuff applied to opponents by Spirit Shredder Bullets behaves differently from all other lifesteal items. It does not affect the user's Spirit Lifesteal stat, nor is it factored into the multiplicative formula; instead, it adds a flat +8% spirit lifesteal against an affected target while the debuff is active.

For example, if a player has Spirit Lifesteal (+16%) and Leech (+30%), their base spirit lifesteal is 41.2%. Against a target affected by Soul Shredder Bullets, it would be:

$\text{Total Lifesteal}=[1-(1-0.16)\times (1-0.30)]+0.08=49.2\mathrm{\%}$

Melee Lifesteal

Main articles: Melee Lifesteal, Lifestrike

Melee Lifesteal is not a stat. The item Melee Lifesteal and its upgrade Lifestrike both provide a passive ability which heals the user by a percentage of their melee damage dealt, but they behave differently from Bullet and Spirit Lifesteal.

These abilities activate for one melee attack, then go on cooldown for several seconds, during which no further health can be regained from melee attacks. In contrast, Bullet and Spirit Lifesteal are always active and have no cooldowns. These items also grant a flat healing bonus on activation, and are less effective against non-heroes.