Turn rate

Turn rate is the speed at which a unit can turn. When moving to a location, a unit first turns to face that location, then begins walking. Similarly, when targeting another unit with an attack or spell, a unit first turns until it is facing the target, then continues with the action. A unit only starts moving, or only starts casting a spell on a targeted area or point when the target is within 11.5° angle in front of the ordered unit. This can make kiting more difficult, as the hero has to spend time turning towards and away from the target with each attack.

Every unit has a base turn rate, which can be lowered by some abilities. The vast majority of heroes have a turn rate between 0.4 and 0.6, meaning it takes between 0.15 and 0.23 seconds for the hero to make a 180 degree turn.

Mechanics
Turn rate is expressed in radians per 0.03 seconds. A 180 degrees turn is the same as π (3.14) radians.

0.03π divided by your turn rate equals to the time it takes to turn 180 degrees. A turn rate slow is directly applied to your base turn rate. For example, a turn rate slow of 70% on your 0.5 base turn rate lowers your actual turn rate to [0.5 (1-0.7)] = 0.15.

(0.03π / T = t, where T = turn rate and t = the time it takes to turn around).

Examples:


 * 1) A hero with a turn rate of 0.6 takes roughly 0.157 seconds to turn 180 degrees. (0.03π / 0.6)
 * 2) A hero with a turn rate of 0.4 and a turn rate slow of 70% takes roughly 0.785 seconds to turn 180 degrees. (0.03π / (0.4 * 0.3))
 * 3) A hero with a turn rate of 1.0 and a turn rate slow of 70% takes roughly 0.314 seconds to turn 180 degrees. (0.03π / (1.0 * 0.3))
 * 4) A hero with a turn rate of 0.4 and turn rate slows of 70% and 50% takes roughly 1.571 seconds to turn 180 degrees. (0.03π / (0.4 * 0.15))

If a unit starts turning due to an ability or item cast order (by targeting a point, area or unit which is not within the required 11.5° facing angle), the turning cannot be canceled by a move, attack or a new spell cast order. Any command ordered while turning due to a spell cast order gets queued up and executed once the spell is cast. In order to cancel the spell or ability cast, the player must issue a stop or halt command, in the same way how to cancel spell during its cast animation. This is to prevent accidental canceling of casts due to fast clicking. Issuing a stop or halt command does not stop the from turning if it already started to turn, but stops the order which initiated the turning. This allows for example Templar Assassin to turn during Meld without canceling the ability, as long as the move command is stopped before the targeted point is within the required angle.

Turn rate comparison
Below is a comparison of the turn rates of all Heroes.
 * : Despite not requiring to turn to take any action, Io still uses a turn rate (0.7). This means, despite starting to move/attack/cast spells instantly at target behind it, Io still requires roughly 0.13 seconds to turn 180° and face towards the target. This still existing turn rate affects spells which work with the facing angle of unit, like, and . Its front is marked by an arc.
 * During, , and , the caster does not require to turn to take actions either.
 * ,, , , , and  do not require their casters to face towards their target.