Enter the mass (kg) and the velocity (m/s) into the calculator to determine the Relativistic Energy. 

Relativistic Energy Formula

The following equation is used to calculate the Relativistic Energy. 

KE = m*c^2 * (SQRT(1-V^2/C^2)-1)


  • Where KE is the Relativistic Energy (Joules)
  • m is the mass (kg) 
  • V is the velocity (m/s) 
  • c is the speed of light (299,792,458 m/s)

How to Calculate Relativistic Energy?

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

Example Problem #1:

  1. First, determine the mass (kg). In this example, the mass (kg) is measured to be 95.
  2. Next, determine the velocity (m/s). For this problem, the velocity (m/s) is calculated to be 4.
  3. Finally, calculate the Relativistic Energy using the formula above: 

KE = m*c^2 * (SQRT(1-V^2/C^2)-1) = (Joules)

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

KE = 95*299792458^2 * (SQRT(1-4^2/299792458^2)-1)

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: 

mass (kg) = 93

velocity (m/s) = 3

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

KE = 93*299792458^2 * (SQRT(1-3^2/299792458^2)-1) = (Joules)