Science Calculators
Photon Energy Calculator
Enter a wavelength to calculate the energy of a single photon of light at that wavelength.
Energy (Joules)
3.9756e-19 J
Energy (electron volts)
2.482 eV
Uses the Planck-Einstein relation E = hc/λ, with Planck's constant h = 6.626×10⁻³⁴ J·s and the speed of light c = 3×10⁸ m/s. Shorter wavelengths carry more energy per photon.
How to use this tool
- 1Enter the wavelength in nanometers.
- 2See the photon's energy in joules and electron volts.
Frequently asked questions
Why do shorter wavelengths have more energy?+
Photon energy is inversely proportional to wavelength (E = hc/λ) — that's why high-energy radiation like X-rays and gamma rays has much shorter wavelengths than visible light or radio waves.