# Photon energy calculator

Input
Output

eV

J

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This calculator computes the energy of a photon from its vacuum wavelength $\lambda$, frequency $\nu$ or wavenumber $\kappa$. The photon energy is
$E_{p} = h\nu = \dfrac{hc}{\lambda} = hc\kappa$
where $h \approx 6.626\cdot 10^{-34}$ is the Planck constant and $c$ is the speed of light in vacuum. Energy is converted to electronvolts by dividing it by the elemental charge $e \approx 1.602 \cdot 10^{-19}$.