Enter the energy and speed of light into the calculator to determine the mass. This calculator can also evaluate any of the variables given the others are known.

Joules To Kg Formula

The following formula is used to calculate mass from energy.

m = E / c^2


  • m is the mass (kg)
  • E is the energy (Joules)
  • c is the speed of light in a vacuum (m/s^2), approximately 3.00 x 10^8 m/s

To calculate the mass, divide the energy by the square of the speed of light. This will give you the mass equivalent of the energy in kilograms.

What is Joules To Kg?

Joules to Kg is a conversion from energy (measured in Joules) to mass (measured in kilograms) based on Einstein’s equation E=mc^2, which states that energy and mass are interchangeable. This conversion is not common in everyday scenarios but is used in high-energy physics and quantum mechanics. It’s important to note that this doesn’t mean energy is being transformed into physical matter, but rather it’s a way of measuring the same phenomenon in two different ways.

How to Calculate Joules To Kg?

The following steps outline how to calculate the mass (m) in kilograms using the formula: m = E / c^2.

  1. First, determine the energy (E) in Joules.
  2. Next, determine the speed of light in a vacuum (c) in meters per second squared (m/s^2). Use the value of approximately 3.00 x 10^8 m/s.
  3. Next, substitute the values of E and c into the formula: m = E / c^2.
  4. Finally, calculate the mass (m) in kilograms.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem:

Use the following variables as an example problem to test your knowledge.

energy (E) = 2.5 x 10^9 Joules

speed of light in a vacuum (c) = 3.00 x 10^8 m/s