Photon Energy Calculator
Calculate the energy of a single photon from its wavelength or frequency using the Planck-Einstein relation.
What photon energy is
Light behaves as discrete packets of energy called photons. The energy carried by a single photon depends only on its frequency (or equivalently, its wavelength) — higher frequency, shorter-wavelength light such as blue or ultraviolet carries more energy per photon than lower frequency, longer-wavelength light such as red or infrared.
The formula
Photon energy is calculated with the Planck-Einstein relation, E = h × f, where h is Planck’s constant (6.62607015 × 10⁻³⁴ J·s) and f is frequency in hertz. If you provide a wavelength instead, the calculator first converts it to frequency using f = c / λ, where c is the speed of light in a vacuum (299,792,458 m/s). The result is shown in both joules and electronvolts (eV), a convenient unit for atomic-scale energies.
This calculator assumes light traveling in a vacuum. This tool is for general educational and study purposes.