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 a low base attack speed will receive less of an attack speed boost from the bonus than champions with a high base attack speed, but the proportional increase in DPS will remain the same for both. 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.

Base attack speed
Every champion's "base attack speed" (ASbase) is calculated using a hidden variable called "attack delay." Attack delay is a number between &minus;0.10 and 0.08:


 * ASbase0.625(1attack delay)

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

Bonus attack speed sources

 * Champions gain AS% at each level, not including level 1. This amount ranges from roughly 0% to 4% and depends on the champion.
 * Items
 * Champion abilities
 * The mastery
 * The mastery
 * runes

Bonus AS% stacks additively.


 * Example: grants +40% attack speed and  grants +50% attack speed, so the champion gains +90% in total.

Notes:


 * Final attack speed cannot go above the cap of 2.5 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&minus;0.04.
 * 0.625(10.04)0.6250.960.651041 6 . 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 he has gained 3.22%17 = 54.74% as bonus AS%.
 * At 18 he has maxed increasing his attack speed by 30%.
 * Let's say he has the mastery up to 4%.
 * Let's also say he has : +50%.
 * All together he has: 54.74%30%4%50%138.74% as bonus AS% or 1.3874 bonus AS as a decimal.
 * Final calculation:
 * (0.6250.96)(11.3874).
 * 0.651041 6 2.38741.554296716.
 * In game, the number will be shown as: 1.554.

Champion abilities
Note: Only the attack speed buff effect of these abilities is shown here, to read more information on each of these abilities, follow the link on each of them.
 * increases his attack speed by for 8 seconds.
 * passively grants Diana 20% bonus attack speed.
 * increases his attack speed by for 3 seconds.
 * increases the attack speed of herself and her Spiderlings by for 3 seconds
 * increases her attack speed by for 3 seconds after attacking with.
 * passively increases his attack speed by 10% whenever he hits a target with any of his abilities. This bonus lasts for 6 seconds and stacks up to 5 times.
 * increases the attack speed of allied champions it passes through by for 5 seconds.
 * increases her attack speed by for 3 seconds.
 * increases his attack speed by for 4 seconds.
 * passively increases his attack speed by . When activated, it throws a flag that increases nearby allied champions and his own attack speed again by the same amount.
 * causes his basic attacks to increase his attack speed by %. This bonus lasts for 2.5 seconds and stacks up to six times.
 * increases his attack speed by 300% for three basic attacks.
 * reduces magic damage taken by 15% and transforms this damage into bonus attack speed. This effect stacks individually and each individual buff lasts up to 4 seconds.
 * passively increases his attack speed by.
 * increases the attack speed by 40% of his next two 2 autoattacks within the next three seconds after casting an ability.
 * increases his attack speed by for  seconds.
 * increases her attack speed by for 6 seconds.
 * increases her or an allied unit's attack speed by for 7 seconds.
 * passively grants himself attack speed. Upon activation, it summons a spell shield for 1.5 seconds, if the shield successfully blocks a spell, the attack speed bonus is doubled for 5 seconds.
 * increases an allied unit's and his own attack speed by for 12 seconds.
 * passively increases his attack speed by 1% per 1% health he is missing.
 * increases his attack speed by for 4 seconds, while his  increases his attack speed by  for 4 seconds. These effects can stack for a total of.
 * increases his attack speed by 50% for 20 seconds.
 * grants her an aura for 10 seconds that increases her attack speed by and one half of that to nearby allies.
 * grants him a shield for up to 6 seconds, while the shield persists Skarner increases his attack speed by.
 * increases his attack speed by 40% for 3 seconds after leaving his stealth state.
 * increases her attack speed by for 7 seconds.
 * coats the target location with ice for 8 seconds, while on this area, Trundle increases his attack speed by.
 * passively increases his attack speed by.
 * increases his attack speed by for up to 5 seconds after revealing himself.
 * increases his attack speed by 10% upon switching stances. This bonus lasts for 5 seconds and stacks up to 3 times.
 * increases his attack speed by  for 5 seconds on activation.
 * increases attack speed by 20% for 3 seconds on minion kills, while a champion kill/assist will grant 40% for 6 seconds.
 * will increase Vi's attack speed by for 4 seconds after attacking the same target 3 times.
 * passively causes his autoattacks to increase his attack speed by . This bonus stacks up to 3 times and lasts for 4 seconds.
 * increases his attack speed by and half of that amount to nearby allied champions for 10 seconds.
 * increases his attack speed by after hitting a target with this skill.
 * increases his attack speed by for 5 seconds.

Masteries

 * increases your champion's attack speed by.
 * grants 10% attack speed to your champion for 2 seconds after landing a critical hit.

Runes

 * runes increase attack speed.

Reducing attack speed
Note: Attack speed reductions stack multiplicatively and take percentages off the final attack speed value after all bonus attack speed has been factored in.

Items

 * : Unique Aura: Reduces the attack speed of nearby enemies by 20%.
 * : Unique Passive - Cold Steel: If you are hit by a basic attack, you slow the attacker's attack speed by 15% and their movement speed by 10% for seconds.
 * : Unique Passive - Cold Steel: If you are hit by a basic attack, you slow the attacker's attack speed by 15% for seconds.

Champion abilities
Note: Only the attack speed reduction effect of these abilities is shown here, to read more information on each of these abilities, follow the link on each of them.
 * slows affected units' attack speed by 20% for 1 second.
 * slows affected unit's attack speed by for 2 seconds.
 * slows affected units' attack speed by for 3 seconds.
 * slows affected units' attack speed by for 4 seconds.
 * slows affected units' attack speed by for 3 seconds.
 * reduces an enemy unit's attack speed by 17.5% plus an additional per second for 5 seconds.
 * slows the attack speed of all nearby enemy units by 25% while channeling for 3 seconds.
 * reduces an enemy unit's attack speed by 25% for 3 seconds.

Neutral monsters

 * The attacks will slow the attacked champion's attack speed by 20% for 4 seconds.