Attack speed

Attack speed (often shortened as AS or ASPD) is the frequency of a champion's basic attacks. They are measured and displayed as attacks per second.
 * Attack speed cannot be increased beyond attacks per second (or 1 attack every two fifths of a second, or  seconds).
 * bypasses this limit (up to attack per second).

Attack speed bonuses (from items or abilities, etc.) are in percent. The bonus is a percentage of the champions base attack speed. Therefore, champions with higher base attack speed benefit more from attack speed increases. Like all stats, one's attack speed can be increased via leveling up, items, runes, masteries, buffs, and abilities. Some items and abilities (only those two) decrease enemy attack speed.

Base attack speed
Every champion's base attack speed (ASbase) is calculated using a hidden variable called attack delay, which ranges from &minus; to. (ASbase) is the total number shown at level 1 without runes, masteries, etc. It is represented this way throughout the wiki.

$$\pagecolor{Black}\color{White}{\it AS}_{\rm base} = {0.625 \over 1 + {\it attack\ delay}}$$

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. This amount depends on the level through the Statistics growth formula.
 * Items
 * Champion abilities
 * Masteries
 * runes

Bonus AS% stacks additively.


 * Example: grants +35% attack speed and  also grants +50% attack speed, so the champion gains +85% in total.

Notes:
 * Final attack speed cannot go above the cap of  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.

Example

 * Calculating base attack speed:
 * attack delay is &minus;0.04.
 * $$\pagecolor{Black}\color{White}{0.625 \over (1 - 0.04)} = {0.625 \over 0.96} = 0.651041 \overline{6}$$. 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 bonus AS% based on percentage growth 3.22% and his level through the Statistics growth formula.
 * At level 18 he has gained $$\pagecolor{Black}\color{White}3.22\% \times\left({7 \over 400}\times(18^2-1)+{267\over400}\times(18-1)\right)=54.74\%$$ 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 : +35%.
 * All together he has: 54.74% + 30% + 4% + 35% = 123.74% bonus AS% or bonus AS as a decimal.
 * Final calculation:
 * $$\pagecolor{Black}\color{White}\begin{align} & {0.625 \over 0.96} + \left({{0.625 \over 0.96} \times 123.74\%}\right) \\ =& 0.651041\overline6 + ({0.651041 \times 123.74\%}) \\ \approx & 1.45664 \end{align}$$
 * In game, the number will be shown as: 1.457.

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.


 * passively increases his attack speed by % for every 2% in the Blood Well.
 * increases his attack speed by for 12 seconds.
 * increases his attack speed by for 5 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 50% for her 2 next basic attacks.
 * increases his attack speed by % when in.
 * increases his attack speed by  for 3 seconds.
 * passively increases his attack speed by . When activated, it throws a flag that increases nearby allied champions and his own attack speed by the same amount.
 * causes his basic attacks to increase his attack speed by %. This bonus lasts for seconds and stacks up to eight times, falling off one stack at a time every 0. 25  seconds.
 * increases his attack speed to for three basic attacks.
 * causes her basic attacks to grant bonus attack speed for seconds, stacking up to three times (up to ).
 * grants her 15% total attack speed for 6 seconds whenever an enemy champion or structure dies within 3 seconds of being damaged by her.
 * makes him periodically enter a frenzy that grants him 150% bonus attack speed on his next 4 attacks for 4 seconds.
 * passively increases his attack speed by, and, upon activation and for 6 seconds, double his total attack speed.
 * increases the attack speed by 40% of his next two 2 autoattacks within the next three seconds after casting an ability.
 * casts erratic magic upon the target champion, giving them % bonus attack speed and bonus movement speed for the next few seconds if they are an ally.
 * increases his attack speed by for 7 seconds. Kills and assists extends the duration by 7 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  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.
 * increases his attack speed by for 6 seconds.
 * increases Quinn's attack speed by for 3 seconds when she attacks a target marked by.
 * passively grants her % bonus attack speed.
 * increases his attack speed by bonus 47 + (3Rengar's level) % for 5 seconds
 * passively grants her attack speed while  is active.
 * increases his attack speed by % for 3 seconds after leaving his stealth state.
 * increases her attack speed by for 5 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 auto attacks 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 6 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.

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 15%.
 * : Unique Passive – : If you are hit by a basic attack, you slow the attacker's attack speed by 15% for 1 second.
 * : Unique Passive – : If you are hit by a basic attack, you slow the attacker's attack speed by 15% for second.

Summoner Spells

 * : Active: Exhausts target enemy champion, reducing their movement speed and attack speed by 30%, their armor and magic resist by 10, and their damage dealt by 40% 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 enemy champion's attack speed by 50% for 1. 5  seconds.
 * slows affected units' attack speed by for 3 seconds.
 * reduces an enemy unit's attack speed by 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.

Trivia
Last updated: May 28st 2016 - V6.10
 * The most attack speed a champion can reach at level 1 with the initial is  with.
 * With no particular context, the amount of bonus attack speed required for to reach the AS cap is 300%.
 * Base AS: 
 * Bonus AS: 
 * Runes: 
 * 9GMarks (2).png Marks of Attack Speed (+9% AS)
 * 9GSeals (3).png Seals of Attack Speed (+9% AS)
 * 9GGlyphs (3).png Glyphs of Attack Speed (+9% AS)
 * 3GQuintessences (3).png Quintessences of Attack Speed (+3% AS)
 * Masteries: 
 * 5 points in (+4% AS)
 * Item: 
 * One (+12% AS)
 * Buffs: 
 * (+20% AS)
 * (+20% AS)
 * (+25% AS)
 * (+20% AS)
 * '''AS Amplification:
 * (+100% Total AS)
 * Relevant mathematics:
 * Total AS(1)
 * Bonus AS%85% AS
 * Runes
 * Buffs
 * Bonus AS for the cap4300% Bonus AS