Attack speed

Attack Speed (often shortened as AS or ASPD) is the frequency at which a champion performs basic attacks and are displayed as "attacks per second". Attack speed caps at 2.5 attacks per second, or 1 attack every two fifths of a second.

Attack speed bonuses works by adding a percentage of a champion's base attack speed to his or her "base attack speed". Champions with low base attack speed will benefit less from increased attack speed than champions with high base rate of attack. One's attack speed can be increased via leveling up, items, runes, masteries, buffs, and abilities. One's attack speed can only be decreased by items, abilities, and the Dragon.

Base attack speed
Every champion's "base attack speed" (ASbase) is calculated using a hidden variable called "attack delay". Attack delay is a number (up to 2 decimal places) between -0.1 and +0.08:

ASbase = 0.625 / (1 + attack_delay)

This value is the the total number shown at level 1 without runes, masteries, etc. It is represented this way throughout the wiki.

Final Attack Speed
Attack Speed (AS) is then calculated using the following formula:

AS = ASbase * (100% + bonus_AS%)

The bonus AS% can come from 6 sources:
 * Every time a champion levels up, bonus AS% is added (between 1.00% to 4.00%, up to 2 decimal places, depending on the champion). (This is the growth shown on the wiki champion's pages).
 * Items.
 * Champion Abilities.
 * Masteries: and.
 * Runes:.
 * The buff.

All bonus AS% is additive, except for the mastery, which multiplies bonus attack speed. This means that you receive no benefit from it if you don't have any other bonus attack speed.

For example:
 * 40%  + : 50% = 90 bonus AS%
 * (: 40% + : 50%) * : 1.04 = 93.6 bonus AS%

Notes:


 * Attack speed cannot go above the cap of 2.500 attacks per second.


 * Many in-game tooltip percentages (such as runes) have been rounded, so results may be slightly different unless the precise numbers are known.

Calculation Example
 * Calculating "base attack speed":
 * attack_delay = -0.04.
 * 0.625 / (1 - 0.04).
 * 0.625 / 0.96 = 0.651041666666 (repeating decimal). This is base attack speed, seen at level 1 (without runes, masteries, etc).
 * The number seen in game is rounded to 3 decimal places: 0.651.
 * Calculating "bonus attack speed":
 * Every time levels up, he gains 3.22% as bonus AS%.
 * At level 18 (after leveling up 17 times) he has gained 3.22% * 17 = 54.74% as bonus AS%.
 * At 18 he has maxed increasing his attack speed by 15%.
 * Let's say he has the mastery up to 4%.
 * Let's also say he has : +55% and : +60%.
 * All together he has: 54.74 + 15 + 4 + 55 + 60 = 188.74% as bonus AS%.
 * But he also has mastery up to 4%. So all the bonus AS% is multipled by 1.04.
 * 188.74% * 1.04 = 196.29.
 * Final calculation:
 * ( 0.625 / 0.96 ) * (100% + 196.29%).
 * 0.65104166666 (repeating) * 296.29% = 1.9289713541666 (repeating).
 * In game, the rounded number will be shown as: 1.929.

Items

 * : +25% Attack Speed, UNIQUE Passive: Enhanced Movement 2. 920 Gold
 * : +20% Attack Speed, +20% Critical Chance, +25 Tenacity. 1450 Gold
 * : +15% Attack Speed.  420 Gold
 * : +35 Attack Damage, +45 Ability Power, Passive: On attack or spell cast, increases your Attack Speed by 4% and Ability Power by 6. Lasts 5 seconds (stacks up to 8 times). 2235 Gold
 * : +30 Attack Damage, +40% Attack Speed, +25 Armor UNIQUE - On hit, deals Magic Damage equal to 4% of the target's maximum Health. 3800 Gold
 * : +50% Attack Speed, +25 Ability Power UNIQUE Passive: Your physical attacks shred your target doing 20 magic damage and reducing their magic resistance by 6. Stacks 4 times. 1825 Gold
 * : +50% Attack Speed, +55 Ability Power, +10 Mp5 UNIQUE Passive: Reduces ability cooldowns by 25%. 2885 Gold
 * : +55% Attack Speed, +30% Critical Chance, +15% Movement Speed. 2895 Gold
 * : +40% Attack Speed. 1050 Gold
 * : +20% Attack Speed, UNIQUE Aura: Gives nearby allied Champions 20% Lifesteal, 20% Attack Speed, and 30 Hp5. Reduces the armor of nearby enemy champions by 20. 2550 Gold
 * : +40% Attack Speed UNIQUE Passive: Reduces ability cooldowns by 10%. 1140 Gold
 * : +60% Attack Speed UNIQUE Passive: Every fourth attack deals 100 extra Magic Damage, UNIQUE Active: Your attacks cannot be dodged and you gain 30 Armor Penetration for 8 sec. (40 second cooldown). 1970 Gold
 * +30% Attack Speed, +55 Damage. Passive: Physical attacks reduce your target's Armor by 15 for 5 seconds, (maximum 3 stacks). 2865 Gold
 * : +30 Damage, +30 Ability Power, +30% Attack Speed, +15% Crit Chance, +12% Move Speed, +250 Health, +250 Mana, UNIQUE Passive: 25% chance on hit to slow the target by 35% for 2.5 seconds; on cast, adds bonus damage equal to 150% of base damage. 4070 Gold
 * : +40% Attack Speed, +30 Magic Resist, UNIQUE Passive: Your attacks deal 42 bonus magic damage and increase your magic resistance by 5 for 5 seconds (stacks up to 4 times). 2000 Gold
 * : +30 Attack Damage, +15% Critical Chance UNIQUE Passive: Gives 20 Armor Penetration and 15% Cooldown Reduction, UNIQUE Active: Gives 20% movement speed and +50% attack speed for 4 seconds. Attacking enemy units with melee attacks increases the duration by 2 to a maximum of 8 seconds. 60 second cooldown. 2687 Gold
 * : +20% Attack Speed, +10% Critical Chance, +8% Movement Speed. 1195 Gold

Consumable

 * : +12-22% Attack Speed, based on champion level, and 8% Critical Chance for 4 minutes. 250 Gold

Champion Abilities

 * increases his attack speed by 30/38/46/54/62% for 8 seconds.
 * increases her attack speed by 25/50/75% for 10 seconds.
 * increases his attack speed by 10% for 6 seconds when he hits a target with any of his abilities (stackable up to 5 times).
 * increases the attack speed of allied champions it passes through by 20/25/30/35/40% for 5 seconds.
 * increases his attack speed and his allies attack speed by 10 / 14 / 18 / 22 / 26%.
 * causes his basic attacks to increase his attack speed by 6/10/14% for 2.5 seconds (stackable up to 10 times).
 * He takes 10% reduced magic damage and transforms this damage into bonus attack speed. This effect lasts up to 4 seconds.
 * increases his attack speed by 10/15/20/25/30%.
 * increases his attack speed by 50% for 2 basic attacks after casting an ability
 * increases his attack speed by 40/60/80% for 6/9/12 seconds.
 * increases her attack speed by 30/35/40/45/50% for 6 seconds.
 * increases an allied unit's attack speed by 20/30/40/50/60% for 7 seconds.
 * increases an allied unit's and his own attack speed by 25/35/45/55/65% for 15 seconds.
 * gives 20/25/30/35/40% passive attack speed. If the shield successfully blocks a spell, the bonus is doubled for 5 seconds.
 * increases his attack speed by 1% per 1% health missing.
 * increases his attack speed by 50% for 20 seconds.
 * increases her attack speed by 30/60/90% and one third of that to nearby allies for 15 seconds.
 * increases his attack speed by 40% for 3 seconds when he attacks while stealthed.
 * increases her attack speed by 30/45/60/75/90% for 7 seconds.
 * increases his attack speed by 3/6/9/12/15%.
 * increases his attack speed by 30/40/50/60/70% for up to 10 seconds depending on how long he was stealthed before attacking.
 * increases his attack speed by 10% for 5 seconds upon switching stances (stackable up to 3 times).
 * increases his attack speed by 20/25/30/35/40%, and for additional 15/20/25/30/35% for 5 secs on activation.
 * increases his attack speed by 40/50/60/70/80% and half of that to nearby allied champions for 10 seconds.
 * increases his attack speed by 20/25/30/35/40%. He can activate this ability to double the effect for 7 seconds.

Masteries

 * increases your champion's attack speed by 1/2/3/4%.
 * increases your champion's ability power and bonus attack speed by 1.33/2.66/4%.

Runes

 * runes increase attack speed.

Neutral Buffs

 * The buff gives 20% increased attack speed.

Decreasing Attack Speed
Note: Attack Speed reductions stack multiplicatively, and take percentages off the final AS value after bonus Attack speed has been factored in.

Items

 * : UNIQUE Passive: Reduces the attack speed of nearby enemies by 20%.
 * : UNIQUE Passive: 20% chance on being hit to slow the attacker's movement and attack speeds by 35% for 3 seconds.
 * : UNIQUE Active: Slows movement speeds and attack speeds of surrounding units by 35% for 2 seconds + 0.5 seconds for each 100 Armor and Magic Resist. 60 second cooldown.
 * : Passive: 20% chance on being hit to slow the attacker's movement and attack speeds by 35% for 3 seconds.

Champion Abilities

 * slows affected units' attack speed by 20% for 1 second.
 * decreases the attack speed of enemy champions it passes through by 20/25/30/35/40% for 5 seconds.
 * slows affected units' attack speed by 20/25/30/35/40% for 3 seconds.
 * slows affected units' attack speed by 30/37.5/45/52.5/60% for 4 seconds.
 * slows affected units' attack speed by 30/35/40/45/50% for 4 seconds.
 * reduces an enemy unit's attack speed by 35% plus an additional 3/6/9/12/15% per second for 5 seconds.
 * reduces an enemy unit's attack speed by 25% for 4 seconds.
 * slows the attack speed of all nearby enemy units by 25% while channeling for 3 seconds.

Neutral Monsters

 * The Dragon's attacks will slow the attacked champion's attack speed by 20%.

Final Notes

 * All percentages listed in a champion's Attack Speed statistic are approximations.