Attack Speed

The frequency with which units attack is measured in attack speed. A unit's attack speed can be modified by items, agility, abilities, and auras.

Base attack time
Every unit has a base attack time (BAT), which refers to the default interval between attacks for an unbuffed unit with 0 agility and 0% attack speed. For example, a melee lane creep has a BAT of 1.00 seconds, and thus attacks once every second by default. Similarly, if a hero with 1.7 BAT had 0 agility and no bonus attack speed, they would attack once every 1.70 seconds. While nearly every unit can have their attack speed modified, only a few heroes can actively change their BAT.

All Heroes have a BAT of 1.7 except for the following:


 * Note: Rubick is also capable of lowering his BAT if he steals and uses any of the abilities listed in the above table.

Increased attack speed
Increased attack speed (IAS) gives you a percentage of your base attack speed (or attack per second). Each point in Agility increases IAS by +1. IAS is also modifiable by items, abilities, buffs, and debuffs. Attack speed works together with base attack time to determine how often a unit can attack.

Attack speed caps out at -80% (lowest possible) and +500% (highest possible).


 * Note: When mousing over attack damage in the HUD, the first field shows the attack speed and the time per attack in parenthesis. The attack speed field is defaulted to 100 and adds the IAS afterward, leading to a lower boundary of 20 and an upper boundary of 600. Even though the display may show a unit to "exceed" these boundaries, the actual attack speed used for calculations will still obey the caps of 20 and 600. This can be easily verified by observing that the "time between attacks" display does not change even when pushing well past "600 attack speed".


 * Note2: Units that do not have 1.7 BAT will display their attack speed differently in the in-game HUD as if they had 1.7 BAT. For example, a unit with 0.85 BAT and no bonus attack speed (100 attack speed) will display itself as having 200 attack speed, because 0.85 seconds is how long a unit with 1.70 BAT and 200 attack speed would take in between attacks. This strange quirk makes it harder to figure out if a hero without 1.7 BAT is nearing the attack speed cap, but it does allow players to compare this uniform "attack speed metric" across all heroes more easily.

Attack speed formula
Graph of IAS vs BAT  --->  attacks per second

The formulas below denote the relationship between BAT, IAS, attacks per second, and time between attacks.

(IAS is a percentage, so you must divide your actual IAS by 100 before using it in this formula.)


 * Attack time = BAT / (1 + IAS)
 * Attacks per second = (1 + IAS) / BAT

For example, a lvl 1 Axe with no items has 1.7 BAT and 22 agility, which is converted to (0.22).


 * Attack time = BAT / (1 + IAS)
 * Attack time = 1.7 / (1 + 0.22)
 * Attack time = 1.7 / (1.22)
 * Attack time = ~1.393

>> Axe takes about 1.393 seconds between attacks.


 * Attacks per second = (1 + IAS) / BAT
 * Attacks per second = (1 + 0.22) / 1.7
 * Attacks per second = (1.22) / 1.7
 * Attacks per second = ~0.718

>> Axe attacks about 0.718 times per second.

Remember that units start with 100 attack speed, which caps at 20 and 600. This can be modified by IAS, which therefore caps at -80% and +500%.

Here are some attack speed benchmarks and their affect on attacks per second:


 * -80% attack speed, a unit with 20 AS will take 5/1 times their BAT to attack (1/5x normal speed) (lower cap)
 * -75% attack speed, a unit with 25 AS will take 4/1 times their BAT to attack (1/4x normal speed)
 * -66% attack speed, a unit with 33 AS will take 3/1 times their BAT to attack (1/3x normal speed)
 * -50% attack speed, a unit with 50 AS will take 2/1 times their BAT to attack (1/2x normal speed)
 * +00% attack speed, a unit with 100 AS will take 1/1 times their BAT to attack (1x normal speed)
 * +100% attack speed, a unit with 200 AS will take 1/2 times their BAT to attack (2x normal speed)
 * +200% attack speed, a unit with 300 AS will take 1/3 times their BAT to attack (3x normal speed)
 * +300% attack speed, a unit with 400 AS will take 1/4 times their BAT to attack (4x normal speed)
 * +400% attack speed, a unit with 500 AS will take 1/5 times their BAT to attack (5x normal speed)
 * +500% attack speed, a unit with 600 AS will take 1/6 times their BAT to attack (6x normal speed) (upper cap)

List of items that give increased attack speed
* Item provides increased attack speed exclusively via Agility.