Ability power (AP) is a stat that boosts the effects of some items, abilities, and runes. Those effects receive a bonus proportional to the ability power of the champion. For example, if a champion has 50 ability power and one of their spells deals 100 (+20% AP) damage, the damage of the spell is 110. The spell descriptions in the game do not show that percentage, they show the resulting bonus. The description of the spell in this example would show the damage of the spell as 100 (+10).
Every champion starts with 0 ability power, and level-ups do not grant additional ability power.
Ability power can be increased with items, abilities and runes, it 
stacks additively, and each bonus point acquired directly affects its statistic.
- Ability power has a gold value of
21.75 per point.
Ability power as scaling
Many champion abilities use the champion's ability power to calculate the magnitude of that ability.
The following 20 champions do not have ability power ratios on any on their abilities: 
Aatrox, 
Camille, 
Darius, 
Draven, 
Garen, 
Kalista, 
Kayn, 
Kindred, 
Kled, 
Olaf, 
Pyke, 
Riven, 
Samira, 
Sett, 
Talon, 
Urgot, 
Vayne, 
Xayah, 
Yone, 
Zed.
Items
Runes
Neutral buffs
Increasing ability power
Items
Champion abilities
Runes
Neutral Buffs
Decreasing ability power
Champion abilities
Trivia
- The ability with the largest AP ratio is
Annie's Summon Tibbers, with a maximum AP ratio of (+ 615% AP) counting initial cast of (+ 75% AP) and the target taking damage from all 45 ticks of Tibbers aura damage ((+ 12% AP) per tick). - The second and third bounces of Nami's Ebb and Flow scale exponentially, however the low base ratio means it will not beat other spells at normal levels of AP.
Last updated: September 10, 2020, patch V10.18
- Disregarding Veigar, Thresh, Gathering Storm, and Vladimir with Grasp of the Undying, Overgrowth, or Prototype: Omnistone the highest attainable ability power by a champion on Summoner's Rift is a level 18 Viktor with 2199.648 AP.
- Runes:
- Items:
- 1 × Perfect Hex Core
- 1 × Rabadon's Deathcrown
- 1 × Rabadon's Deathcap
- 1 × Spellbinder
- 1 × Mejai's Soulstealer
- 1 × Seraph's Embrace
- 1 × Elixir of Sorcery (consumed)
- 1 ×
- Other Buffs:
- Viktor:
Last updated: July 28, 2020, patch V10.15
- The highest attainable ability power by a champion at level 1 is 88.928 AP on Viktor.
- Runes:
- Items:
- 1 × Amplifying Tome
- 1 × Prototype Hex Core
- 1 ×
- Other Buffs:
| Offensive | Ability power ·  Attack damage ·  Attack speed ·  Critical strike chance ·  Critical strike damage ·  Armor penetration ·  Magic penetration ·  Life steal ·  Omnivamp · Physical vamp ·  True damage
|
|---|---|
| Defensive |   Heal and shield power ·  Health ·  Health regeneration ·  Armor ·  Magic resistance ·  Tenacity ·  Slow resist
|
| Utility |  Ability haste ·  Energy ·  Energy regeneration ·  Mana ·  Mana regeneration
|
| Other |  Experience ·  Gold generation ·  Movement speed ·  Range
|
