Switch between eV scales and joules fast. Control digits, notation style, and unit prefixes freely. See clear steps, export results, and verify examples here.
The electron volt (eV) is the energy gained by an electron moving through 1 volt.
| Energy (eV) | Energy (J) | Typical Context |
|---|---|---|
| 1 eV | 1.602176634e-19 J | Atomic scale energy steps |
| 10 eV | 1.602176634e-18 J | Ionization and excitation energies |
| 1 keV | 1.602176634e-16 J | X-ray photon energies |
| 1 MeV | 1.602176634e-13 J | Nuclear decay energies |
| 1 GeV | 1.602176634e-10 J | High-energy particle physics |
Values use the exact definition of 1 eV in joules.
The electron volt is a compact energy unit for microscopic physics. Many atomic transitions, ionization thresholds, and detector responses fall between a few eV and a few keV. Using eV avoids long strings of zeros that appear when the same energies are written in joules.
By definition, 1 eV is the energy gained by an elementary charge moving through a potential difference of 1 volt. Because the elementary charge is fixed in the SI system, the conversion is exact: 1 eV = 1.602176634 × 10−19 J. This calculator applies that constant directly.
Prefixes scale the electron volt by powers of ten: 1 keV = 103 eV, 1 MeV = 106 eV, 1 GeV = 109 eV, and 1 TeV = 1012 eV. Choosing the right prefix keeps inputs readable and reduces entry mistakes in lab notes and simulations.
Visible photons carry roughly 1.6–3.3 eV, ultraviolet commonly spans 3–100 eV, and characteristic X-rays often sit near 1–100 keV. Nuclear decay energies are frequently reported in MeV, while accelerator beams and cosmic-ray particles are described in GeV to TeV.
Engineering workflows often require joules for power, heat, and dose calculations. For example, converting a MeV-scale decay energy into joules helps estimate total released energy from activity, count rates, or reaction yields. Joules also integrate cleanly with SI-based material properties.
Microscopic energies are extremely small in joules, so scientific notation is usually the safest display. This tool lets you choose significant digits to match measurement resolution. If your input has three meaningful digits, keeping 3–4 significant digits in the output prevents false precision.
Suppose you enter 5.00 keV and convert to joules. First convert to eV: 5.00 keV = 5000 eV. Then multiply by the constant: 5000 × 1.602176634 × 10−19 J ≈ 8.01088 × 10−16 J. The calculator reproduces this value and offers scaled joule outputs.
Confirm the direction before converting. If you see an output near 10−19 J, your input was likely around 1 eV. If converting from joules to eV gives a huge number, that is expected because 1 joule equals about 6.24 × 1018 eV. Use reverse mode to verify critical results.
An electron volt is the energy gained by one elementary charge moving through one volt of electric potential. It is a convenient unit for atomic, photon, and particle energies where joules become extremely small.
That number is the exact SI-defined value for the elementary charge in coulombs. Since 1 eV equals charge times one volt, the joule conversion becomes exact and does not depend on experimental measurement.
One joule equals about 6.241509074×1018 eV. The value is the reciprocal of the eV-to-joule constant, so converting joules to eV naturally produces very large numbers.
Yes in most cases. Joule values for eV-scale energies are typically between 10−19 and 10−13. Scientific notation reduces reading mistakes and keeps the magnitude clear during copying and reporting.
keV is a thousand electron volts, used for microscopic energies. kJ is a thousand joules, used for macroscopic energy and heat. They scale different base units, so they are not interchangeable without conversion.
Yes. Converting MeV to joules lets you multiply by the number of decays or reactions to estimate total released energy. This is useful for yield calculations, thermal loads, and energy bookkeeping in SI units.
Use reverse mode: convert your output back to the original unit and compare. Also sanity-check magnitudes: 1 eV corresponds to about 1.6×10−19 J, and 1 MeV corresponds to about 1.6×10−13 J.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.