Spell vamp

Spell vamp is a defensive stat which converts a percentage of the damage from either champion abilities or item actives into health. It only works for active champion abilities that do not modify basic attacks or apply on-hit effects (including true damage abilities). The exception to this rule is, which does proc all spell effects including spell vamp.

The heal is calculated from damage after being reduced by enemy defense, such as magic resistance, armor or champion damage reduction.

Champion abilities

 * grants % spell vamp for 4 seconds.
 * permanently grants % spell vamp.
 * permanently grants 10/ 15/ 20% life steal.

Ability Drain
Note: ''These abilities will heal the champion by a percentage of the damage dealt from their ability. These act similar to how spell vamp works, but unlike it, they have no penalty for being Area of Effect abilities.''
 * heals for of the damage dealt.
 * heals for 20% of all damage dealt to enemies, from any source, within the ability's radius, capping at against minions or monsters.
 * heals for 10% (25% against champions) of the damage dealt.
 * heals for 100% of the damage dealt.
 * heals for 100% of the damage dealt.
 * heals for 80% of the damage dealt.
 * heals for 15% of the damage dealt.

Calculations
Spell vamp is multiplied by total spell damage to determine the amount of health restored. Area of effect spells only heal one-third the normal amount.
 * Example: Dealing 300 single-target damage with 10% spell vamp will heal for 30. Dealing 300 area of effect damage with 10% spell vamp will heal for 10 for each enemy affected.

Trivia
Last updated: December 29, 2016 - V6.24
 * The maximum achievable spell vamp by a playable champion is % on.
 * Runes: +6% spell vamp
 * 3 (+2%3 spell vamp)
 * Masteries: +2% spell vamp
 * 5 points in (+2% spell vamp)
 * 5 points in (+8% total spell vamp)
 * Items: +25% spell vamp
 * (+15% spell vamp)
 * (+10% spell vamp)
 * (+25% total spell vamp)
 * Buffs: +30% spell vamp
 * (+30% spell vamp)
 * Heal Multiplier: 
 * (+25% heal amp.)
 * (+8% heal amp.)
 * Relevant mathematics:
 * spell vamp:
 * Items = +  = 25%
 * Runes = = 6%
 * Mast. & Buffs = +  = 32%
 * Heal Multiplier =
 * spell vamp = (25% + 6% + 32%)% spell vamp