E = mc² Calculator

  • Enter the mass in the "Mass" field and select the unit of mass.
  • Click "Calculate" to calculate the energy based on the mass and the speed of light.
  • Choose the desired unit for energy from the dropdown.
  • The calculated energy will be displayed in the "Energy" field.
  • Click "Copy" to copy the result to the clipboard.
Energy vs. Mass
Calculation and Explanation

Formula: E = mc²


  • E is the energy in joules (J).
  • m is the mass in kilograms (kg).
  • c is the speed of light in meters per second (m/s), approximately 299,792,458 m/s.

This calculator computes the energy (E) based on the mass (m) entered by the user and the speed of light (c) using the famous equation E=mc².

Calculation History

    What is E = mc²?

    The equation E = mc², which is known as Einstein’s mass-energy equivalence equation, relates energy (E), mass (m), and the speed of light (c).

    In this equation:

    • E represents the energy of an object.
    • m represents the mass of the object.
    • c is the speed of light in a vacuum, which is approximately equal to 299,792,458 meters per second (or about 3 x 10^8 meters per second).

    The equation states that the energy (E) of an object is equal to its mass (m) multiplied by the speed of light (c) squared. In other words, it shows the equivalence between mass and energy. It’s a fundamental concept in physics and is a key component of Albert Einstein’s theory of relativity. This equation is used to describe the incredible amount of energy that can be released in nuclear reactions, such as those in the sun or nuclear power plants.

    All Formulae Related to E = mc²

    E = mc² is a fundamental equation in physics, and it has several related formulae that are derived from it or are used in conjunction with it. Here are some of the important formulae related to E = mc²:

    1. Energy-Mass Equivalence: E = mc²
      • This is the original equation, where E represents energy, m represents mass, and c represents the speed of light.
    2. Relativistic Kinetic Energy:
      • The total energy (E) of an object in motion with velocity v is given by:
      • E = γmc²
      • Where γ (gamma) is the Lorentz factor, and it is calculated as:
      • γ = 1 / √(1 – (v² / c²))
      • This equation accounts for the increase in an object’s energy as it approaches the speed of light.
    3. Rest Energy:
      • The rest energy (E₀) of an object at rest (v = 0) is simply its mass-energy:
      • E₀ = mc²
      • This represents the energy an object possesses even when it’s not in motion.
    4. Relativistic Momentum:
      • The momentum (p) of an object with velocity v is given by:
      • p = γmv
      • This equation describes how momentum changes as an object’s velocity approaches the speed of light.
    5. Total Energy of a Photon:
      • The total energy (E) of a photon (a massless particle) is related to its frequency (f) by:
      • E = hf
      • Where h is Planck’s constant (a fundamental constant of nature).
    6. Mass-Energy Equivalence for Nuclear Reactions:
      • In nuclear reactions, the change in mass (Δm) is related to the released energy (ΔE) by:
      • ΔE = Δmc²
      • This equation quantifies the energy released or absorbed in nuclear reactions.

    Applications of E = mc² Calculator in Various Fields

    The equation E = mc², which represents the mass-energy equivalence, has numerous applications in various fields of science and technology. Here are some key areas where E = mc² calculations find practical use:

    1. Nuclear Physics:
      • Understanding the energy released in nuclear reactions, such as nuclear fission and fusion.
      • Calculating the energy binding atomic nuclei together in terms of mass defect.
    2. Particle Physics:
      • Calculating the energy of high-energy particles, such as electrons, protons, and particles in particle accelerators.
      • Exploring the relationship between mass, energy, and the behavior of subatomic particles.
    3. Astronomy and Astrophysics:
      • Understanding the energy source of stars, including the fusion processes in the sun.
      • Explaining the immense energy released in supernova explosions and black hole formation.
    4. Quantum Mechanics:
      • Describing the behavior of particles at very small scales, where the classical concepts of mass and energy may not apply.
    5. Nuclear Energy:
      • Calculating the energy output and efficiency of nuclear power plants.
      • Assessing the potential for nuclear accidents and the release of energy in nuclear disasters.
    6. Medical Imaging and Therapy:
      • In positron emission tomography (PET) scans, E = mc² is used to convert the annihilation of positrons and electrons into photons for medical imaging.
      • In radiation therapy, the equation helps determine the energy delivered by radiation to treat cancer.
    7. Space Exploration:
      • Calculating the energy required for spacecraft propulsion and the potential energy sources for long-duration space missions.
      • Assessing the feasibility of technologies like nuclear propulsion for interplanetary travel.
    8. Cosmology:
      • Understanding the energy content of the universe and its expansion through the relationship between mass and energy.
    9. Energy Conversion and Storage:
      • Assessing the efficiency and energy storage capacity of various technologies, such as batteries and fuel cells.
      • Evaluating the potential of mass-energy conversion for advanced power sources.
    10. Environmental Science:
      • Assessing the environmental impact of energy generation and consumption, especially in terms of mass-energy equivalence.

    Benefits of Using the E = mc² Calculator

    Using an E = mc² calculator or applying the mass-energy equivalence equation (E = mc²) can offer several benefits in various scientific, engineering, and educational contexts. Here are some of the key advantages of using such a calculator:

    1. Energy-Related Calculations: The calculator allows for quick and accurate calculations of energy (E) when the mass (m) and the speed of light (c) are known. This is particularly useful in situations where energy transformations or conversions are involved.
    2. Understanding Fundamental Physics: Using the calculator can help individuals gain a deeper understanding of the fundamental relationship between mass and energy, as described by Einstein’s theory of relativity.
    3. Nuclear and Particle Physics: In nuclear and particle physics, the calculator is essential for analyzing the energy released or absorbed in nuclear reactions and particle interactions. It helps scientists and researchers make predictions and design experiments.
    4. Astronomy and Astrophysics: Astronomers and astrophysicists use E = mc² to calculate the energy produced by stars, explain supernova explosions, and understand the behavior of celestial objects.
    5. Nuclear Energy and Radiation Safety: In the field of nuclear energy, the calculator is valuable for assessing the energy output and safety considerations in nuclear power plants and for evaluating potential hazards and protective measures related to radiation.
    6. Space Exploration: Engineers and scientists working on space missions use E = mc² to calculate the energy requirements for spacecraft propulsion and the potential energy sources for long-duration missions.


    1. “Beyond Mass and Energy: E = mc² in General Relativity and Cosmology” by Physical Review Letters
    2. “From Nuclear Reactions to Nuclear Power: E = mc² in Energy Production and Nuclear Physics” by Annual Review of Nuclear and Particle Science

    Last Updated : 27 February, 2024

    dot 1
    One request?

    I’ve put so much effort writing this blog post to provide value to you. It’ll be very helpful for me, if you consider sharing it on social media or with your friends/family. SHARING IS ♥️

    21 thoughts on “E = mc² Calculator”

    1. The equation E = mc² revolutionized our understanding of the universe. Its applications are simply mind-blowing.

    2. The E = mc² equation has played a crucial role in advancing our knowledge of nuclear physics, particle physics, and cosmology. Its impact cannot be overstated.

    3. The far-reaching implications of E = mc² underscore its significance as a unifying concept in physics and scientific inquiry.

    4. It’s fascinating to see how E = mc² applies to so many different scientific fields. The impact of this equation is truly profound.

    5. The nuanced applications of E = mc² across fields such as nuclear energy, quantum mechanics, and medicine highlight its enduring relevance in modern science and technology.

    6. The E = mc² calculator provides a convenient tool for conducting energy-related calculations and assessments across different scientific disciplines.

    7. The practical benefits of using the E = mc² equation and its related calculations cannot be overstated in scientific and engineering contexts.

    8. E = mc² has truly been instrumental in shaping modern scientific research and technological advancements.

    9. E = mc² continues to be a cornerstone in scientific research, offering insights into the fundamental nature of energy and matter.

    10. Absolutely, Dmiller. The equation’s contributions to diverse scientific domains are truly remarkable.

    11. The implications of E = mc² in the context of environmental science underscore its significance in addressing energy-related challenges.

    12. While the concept of mass-energy equivalence may seem abstract, its practical applications across different domains are invaluable.

    13. I agree, Hunter Chris. The real-world implications of E = mc² extend far beyond theoretical physics.

    14. The E = mc² equation has paved the way for numerous breakthroughs in fields ranging from nuclear physics to space exploration.

    15. Absolutely, the E = mc² equation continues to shape our understanding of the physical world and technological advancements.

    Leave a Comment

    Your email address will not be published. Required fields are marked *