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). Kogmaw's Bio-Arcane Barrage bypasses this limit.

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.

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

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.
 * Items
 * Champion abilities
 * Masteries
 * runes

Bonus AS% stacks additively.


 * Example: grants +50% attack speed and  also grants +50% attack speed, so the champion gains +100% 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.
 * \({0.625 \over (1 - 0.04)} = {0.625 \over 0.96} = 0.651041\overline6\). 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  as bonus AS%.
 * At level 18 he has gained \(3.22\% \times 17 = 54.74\%\) as bonus AS%.
 * At 18 he has maxed increasing his attack speed by 30%.
 * Let's say he has the mastery up to 5%.
 * Let's also say he has : +50%.
 * All together he has: \(54.74\% + 30\% + 5\% + 50\% = 139.74\%\) bonus AS% or bonus AS as a decimal.
 * Final calculation:
 * \(\begin{align} & {0.625 \over 0.96} + ({0.625 \times 139.74\%}) \\ =& 0.651041\overline6 + ({0.651041 \times 139.74\%}) \\ \approx & 1.56081 \end{align}\)
 * In game, the number will be shown as: 1.561.

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 (Gnar's level) % when in.
 * 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 six times.
 * 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 ).
 * 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 10 seconds. Kills and assists extends the duration by 4 second.
 * 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.

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 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 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.