Science calculator
Photon energy.
Enter a photon's vacuum wavelength or frequency to find its energy in joules and electronvolts, together with the corresponding wave quantity.
Photon energy Eper photon
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E = hf = hc/λ
- Energy in joules
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- Energy in electronvolts
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- Frequency
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- Vacuum wavelength
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- E energy per photon · h Planck constant · f frequency · c speed of light · λ vacuum wavelength
Assumptions
- Energy is for one photon.
- λ is vacuum wavelength; frequency is unchanged when light enters a medium.
- Uses exact SI values h = 6.62607015 × 10⁻³⁴ J·s, c = 299792458 m/s and e = 1.602176634 × 10⁻¹⁹ C.
- Relativistic photon relation; no material band structure or interaction energy is included.
How it works
Photon energy is proportional to frequency. Higher-frequency radiation carries more energy per photon.
In vacuum, frequency and wavelength satisfy c = fλ, giving the equivalent hc/λ form. Electronvolts are energy units, not electrical potential.
Choose whichever wave quantity you know. Both energy units and the corresponding frequency or wavelength are calculated from the same full-precision result.
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