How to calculate the RPM of drone motors by kv

The brushless motors are commonly used in drone for better performance .in that motor the kv values are denoted in the bell of the motor for example- 2400kv like that

How to calculate the THEORETICAL RPM  of the motor.

   

Kv - 2400

  

RPM = kv * voltage

   

          = 2400 * 12 volt ( example)

         

          = 28,800 RPM

* IT IS AN THEORETICAL VALUE IT MAY SLIGHTLY VARRIES ON PRACTICAL

Image of brushless motors 

In that imgae we can see the kv of that motor which is denoted on the motor.