Attack Speed

Attack Speed ( $$AS$$ ) is the frequency with which units attack is measured. A unit's attack speed can be modified by items, per point of, abilities providing flat bonuses and auras.

Mechanics
Most heroes have a base attack speed and base attack time of and  respectively.

Total attack speed is defined as



With  being the base attack speed,   and   being the flat additive and flat reduction bonuses.

Attack speed bonuses and reductions stack additively by a flat value. Unlike movement speed, there is currently no sources that reduces attack speed by a percentage. By default, the total attack speed value has a minimum of and an maximum value of  and most unit's attack speeds cannot be reduced or increased beyond the values above.

The attack rate is the amount of attacks a unit can launch within a second, and is defined as

With  being the amount of attacks per second (Attack Rate) and   being the base attack time.

Therefore, the time needed per attack a hero launches is defined as



Base Attack Time
Every unit has a base attack time ( BAT ), which refers to the default interval between attacks for a unit without considering and attack speed bonus.

For example, a has a BAT of, and thus attacks once per second by default. Similarly, if a hero with BAT with no  and no bonus attack speed, they would attack once every 1.7 seconds. While nearly every unit can have their attack speed modified, only a few heroes can actively change their BAT.

Examples

 * With a base attack time of, base attack speed and   at level 1. What is 's current attack rate?






 * attacks about times per second in this example, and takes  seconds between attacks.

Benchmark
Most heroes' attack rate is attacks per second. Attack speed is expressed in percent of base attack speed. The base is therefore expressed as. Each point of increased attack speed (IAS) sources add point to it, and attack speed works together with base attack time to determine how often a unit can attack.

When hovering over the hero's attributes in the HUD, the first field shows the attack speed and the time required per attack in parenthesis. The attack speed field is defaulted to and adds the attack speed bonuses or reductions afterwards, leading to a minimum of  and a maximum value of.

Even though the HUD may show a unit to exceed these boundaries, the actual attack speed used for calculations will still obey the minimum and maximum values.

For units that do not have BAT, the attack speed values in the HUD will be displayed as if they have  BAT. For example, a unit with BAT and no other attack speed bonus sources will display itself as having an attack speed of, because  seconds is how long a unit with  BAT and  attack speed would take in between attacks.

This strange quirk makes it harder to figure out if a hero without the standard BAT is nearing maximum attack speed, but it does allow players to compare this uniform metric across all heroes easier.

The following table shows the attack speed benchmarks and their effect on attacks per second:

Exceptions
Most heroes have a BAT of except for the following:

Other Units

 * Summons


 * Neutral Creeps

Base Attack Time Manipulation
Most base attack time manipulation abilities sets the caster's base attack time to a certain value, unless stated otherwise by the ability descriptions.

Attack Speed Limits
Heroes with a unique base attack speed will also have a unique minimum attack speed equal to the difference between the hero's base attack speed and the default base attack speed.

For example, has a base attack speed of, which is  less attack speed than the default. Therefore, his minimum attack speed will be, which is less attack speed than the default  minimum attack speed.

This means despite and  both having the same  BAT, their slowest attack rates are  seconds respectively. This works in reverse for higher base attack speeds —, whose base attack speed is , will have a minimum attack speed of.

However, this minimum attack speed mechanic does not appear to apply to non-hero units. For example, and, who both have  BAT, both have a minimum attack rate of  seconds, despite Roshan having a base attack speed of.

The maximum attack speed of all heroes is. This value does not change based on the heroes' base attack speed. This means that heroes like have a greater attack speed range ( – ), and heroes like  have a lesser attack speed range ( – ) than the average hero ( – ).

Maximum Attack Speed
The following abilities are able to change a unit's maximum attack speed (of ), allowing it to reach even higher values. If a unit is affected by multiple abilities that change the maximum value, the higher value takes priority.

Fixed Attack Interval
The following abilities perform instant attacks based on fixed intervals and they completely ignore the base attack time, attack speed and attack rate of the unit.

Modifying Attack Speed
These abilities increase or decrease a unit's attack speed by a constant value. These bonuses and reductions can not exceed the minimum and maximum attack speed limits.

Items
Many items grant their owners an attack speed bonus, increasing their attack speed when equipped, either by increasing their agililty, or by just giving them a flat bonus.

The following items increase a unit's attack speed. The effects are limited to the item's owner, which must have the item equipped.

Items that provide attack speed bonus by flat amount and agility:

These items have a flat attack speed bonus to the hero who has them equipped.

These items increase the hero's attack speed through the agility they provide.

Patch History
Velocidade de ataque Скорость атаки 攻击速度