Enter the flywheel moment of inertia (kg-m^2) and the angular velocity (rad/s) into the calculator to determine the Flywheel Energy. 

Flywheel Energy Formula

The following equation is used to calculate the Flywheel Energy. 

Ef = .5*I*w^2


  • Where Ef is the Flywheel Energy (Joules)
  • I is the flywheel moment of inertia (kg-m^2) 
  • w is the angular velocity (rad/s) 

How to Calculate Flywheel Energy?

The following two example problems outline the steps and information needed in order to calculate the Flywheel Energy.

Example Problem #1:

  1. First, determine the flywheel momentum of inertia (kg-m^2). In this example, the flywheel moment of inertia (kg-m^2) is measured to be 9.
  2. Next, determine the angular velocity (rad/s). For this problem, the angular velocity (rad/s) is calculated to be 5.
  3. Finally, calculate the Flywheel Energy using the formula above: 

Ef = .5*I*w^2

Inserting the values from above and solving the equation with the imputed values gives: 

Ef = .5*9*5^2 = 112.5 (Joules)

Example Problem #2: 

Using the same process as example problem 1, we first define the needed variables outlined by the formula. In this case, the values are provide as: 

flywheel moment of inertia (kg-m^2) = 9

angular velocity (rad/s) = 3

Entering these values into the formula or calculator above gives us: 

Ef = .5*9*3^2 = 40.5 (Joules)