An attack that deals 250 damage with 20% life steal restores 50 health, before healing modifiers. A spell that deals the same damage might restore none. Life steal heals you from attacks and other damage specifically allowed to use the stat. It does not turn every damaging ability into a heal.
Before buying sustain, work out which part of your combo can use it. Then ask whether the next fight will let you land those hits. A marksman attacking throughout a long exchange gets something different from the purchase than one who has to spend the fight running.
This guide covers modern PC Summoner’s Rift. Calculations are illustrative, not recorded in-client tests. Wild Rift and alternate-mode shops are outside its scope.
Calculate life steal from the damage that actually lands
For ordinary damage that applies life steal at full effectiveness:
Healing before modifiers = qualifying damage after mitigation x life-steal percentage.
Use 0.20 for 20%. The damage input is not your total AD, the number printed on an ability before defenses, or the entire damage total from a fight. It is the portion of the hit that qualifies after the target’s defenses have done their work. The League community wiki’s life-steal reference documents this post-mitigation basis and additive stacking.
Suppose an attack starts at 300 physical damage and defenses reduce that hit to 150. With 20% life steal, the ordinary heal is 150 x 0.20 = 30, not 60. Improving the damage of a qualifying hit can therefore improve its heal without adding another life-steal item. That still leaves the question of whether the damage increase is worth the purchase.
The following examples hold qualifying post-mitigation damage at 250. There are no other healing modifiers, and the attacker is missing enough health to receive the heal.
| Life steal | Healing from the hit | Heal while the attacker has 40% Grievous Wounds |
|---|---|---|
| 10% | 25 health | 15 health |
| 15% | 37.5 health | 22.5 health |
| 20% | 50 health | 30 health |
The final column multiplies the heal by 0.60. The attacker receiving the heal is the one affected by Grievous Wounds; wounding the target would not reduce the attacker’s healing. Grievous Wounds reduces the heal, rather than subtracting 40 percentage points from the life-steal stat.
Nor does a 50-health heal necessarily add 50 to your visible health bar. If you are only missing 12 health, normal healing fills those 12. A specific overheal-to-shield effect, such as Bloodthirster’s, is an additional item mechanic rather than a property of all life steal.
More life steal stacks, but an upgrade consumes its component
Independent life-steal stat bonuses add together. A 7% bonus and a 15% bonus give 22%, before any separate effects that modify the resulting healing.
When an upgrade consumes Vampiric Scepter, use the finished item’s listed life steal. The component’s 7% has been replaced, not saved as another permanent bonus. Only count items you still own.
Does life steal work on abilities?
Some abilities apply it; dealing physical damage is not enough by itself. Two checks are more useful than whether the spell scales with AD: does the ability modify an attack, or does its own description explicitly say that it applies life steal?
Nasus: a spell button that strengthens an attack
Siphoning Strike empowers Nasus’s next attack, while Soul Eater gives him life steal. Pressing Q does not mean the following hit stops being an attack. His increased attack damage can feed his sustain.
Spirit Fire’s area damage does not get the same treatment. The passive supports Nasus’s attacks; it does not turn everything in his kit into healing.
Nasus still needs to reach the wave. If walking up costs more health than the following attack restores, the passive has not made that trade favorable. Recovering once the opponent backs away is different from absorbing free damage to reach a minion.
Samira: life steal can be written into a damage spell
Samira’s Flair and Inferno Trigger explicitly apply life steal. In the current normal-PC data, both use 100% life-steal effectiveness. The value is bound to their current tooltips in the Samira game-data record, a community-hosted mirror of Riot-origin client data.
Here, 100% effectiveness means the spell uses the full amount of life steal she has. It does not mean that all spell damage becomes health. With 15% life steal and 400 qualifying damage, full effectiveness gives 400 x 0.15 = 60 healing before other modifiers.
Her ultimate still needs targets in range and time to deliver its shots. A life-steal calculation based on damage from the whole channel is not the heal she receives if the channel ends early. When assessing a Samira fight, distinguish the damage she could deal from the damage she actually gets to deliver.
An on-hit trigger is not a promise about the whole combo
"Applies on-hit effects" describes an interaction with triggered effects. It should not be read as permission to count every spell, passive, explosion and follow-up in the combo as life-steal damage.
Riot itself corrected an oversimplified explanation in patch 11.1. That historical clarification discussed eligible on-hit effects rather than making physical damage the universal test. Current effect descriptions still matter, especially when an attack contains several separate damage portions.
For an unfamiliar interaction, start with the normal attack, then examine the added effect separately. Ravenous Hydra provides a useful explicit case: its current Ravenous Crescent active says that life steal applies to the damage. You do not need to infer that from the fact that the active deals physical damage.
Life steal, omnivamp and a champion’s own healing
Riot’s 26.18 bugfix removes an Omnivamp interaction from Serpent’s Fang’s Shield Reaver damage. Do not count shield reduction as an extra source of healing in a damage calculation.
Life steal and omnivamp are not interchangeable labels. Life steal centers on attacks and explicitly eligible damage. Omnivamp covers a broader set of damage, with its own source-specific conditions and effectiveness rules. A source of one stat should not be counted as the other.
For example, current Doran’s Blade lists 2.5% omnivamp, not 2.5% life steal. Adding that item to a calculation as if it were a small Vampiric Scepter skips the distinction between the two mechanics. Nor should every omnivamp source be assumed to heal equally from every kind of target or damage.
Then there is Aatrox. Umbral Dash has a passive that heals him from damage dealt to champions. That is a healing rule in his own kit, not evidence that buying life steal makes any physical spell heal. His Darkin Blade can contribute to that native sustain without becoming an ordinary life-stealing attack.
When a fighter restores health during a spell combo, look for the source before copying the build. A heal from the champion’s own kit may not be available to your champion at all.
Which life-steal purchase solves your problem?
The current item values below come from Riot’s item data. These are purchase examples, not a universal build order or a ranking of all sustain items.
Vampiric Scepter buys recovery between exchanges
Vampiric Scepter costs 900 gold and gives 15 AD and 7% life steal. It is a relatively small way to add attack-based recovery while building toward something else.
If you can return to the wave and attack safely after taking poke, repeated heals have time to accumulate. If the opponent zones you away from every minion, the Scepter sits in your inventory doing much less for your health bar.
It also delays whatever you would otherwise buy with those 900 gold. An early Scepter can help you recover between poke exchanges while postponing the component needed for your damage spike. If the next fight starts before you get several safe attacks on the wave, the life-steal part may not have earned much value yet.
Bloodthirster pays for damage, life steal and overhealing
Bloodthirster currently costs 3,400 gold for 80 AD and 15% life steal, plus Ichorshield’s conversion of excess life-steal healing into a shield. Do not judge the whole item by its healing percentage alone. The AD changes qualifying damage, and the shield is a separate reason to prepare before a fight.
A carry who can attack a wave before the next objective may enter healthier than one who arrives immediately after being poked. But Bloodthirster does not grant immunity to being caught. If the enemy kills you before you can attack, the sustain portion has little chance to help during that engage.
Other life-steal purchases answer different needs. Blade of the Ruined King includes attack speed and an on-hit damage effect; Ravenous Hydra brings damage to nearby enemies and an active. Their life-steal values are only part of the comparison. Buying whichever has the largest percentage ignores the job of the rest of the item.
Diagnose weak healing before adding another item
You bought the sustain item, got a few attacks off, and still feel one spell away from dying. Check what happened before spending another slot on the same solution.
- Did the damage qualify? A large ability number does not prove that the spell applies life steal. Separate attacks, explicit exceptions and native heals.
- How much eligible damage survived mitigation? Against a heavily armored target, the physical part of an attack may produce less healing than expected. Lethality and armor penetration can change that damage, but the correct whole-item choice still depends on the build.
- Were you wounded, at nearly full health, or unable to attack? Reduced healing, overhealing and lost attack time can all make a sustain purchase look ineffective for different reasons.
Life steal can also recover health from ordinary attacks on minions and monsters; it is not restricted to hitting champions. Do not expect the same recovery while attacking a turret. The documented structure exception excludes ordinary life steal from damage against structures.
A safe target is valuable because it gives you attacks you can actually complete. Suppose the opposing tank is in range while the enemy carry is beyond their frontline. Chasing the carry for a theoretically larger heal may cost several attacks and expose you to control. Evaluate the hits you can land from your current position before walking through the fight for a better damage number.
Buy sustain when the next wave or fight gives you enough safe attacks to use it. If you keep dying during the first stun and burst, prioritize surviving that opening. The opportunity to heal comes afterward.