Electronvolts (eV) to Joules Converter

About this calculator

The electronvolt (eV) is the energy gained by a single electron accelerating through a potential difference of one volt — a convenient scale for atomic and subatomic physics, where a joule is astronomically too large. Since the 2019 SI redefinition fixed the elementary charge exactly, the conversion is now an exact constant: 1 eV = 1.602176634 × 10⁻¹⁹ J. Multiplying by Avogadro's number converts eV per particle into kJ/mol, the standard chemistry energy scale.

Particle and nuclear physicists work natively in eV, keV, MeV and GeV to express particle energies, binding energies, and photon energies (via E = hc/λ); chemists convert to kJ/mol to compare against bond energies and reaction enthalpies measured on a per-mole basis.