ONE FORMULA, ONE ANSWER
Photon Energy from Wavelength Calculator
Convert a vacuum wavelength to single-photon energy for basic spectroscopy. Choose input units and calculate one value within the stated conditions.
Inputs
Calculations run in this browser. Scientific notation such as 1.2e-3 is supported. Do not group thousands.
Result
Single-photon energy E
Enter values and select Calculate.
E = h c₀ / λ₀
Assumptions
Use λ₀>0. Do not enter an in-medium wavelength as a vacuum wavelength. Selecting eV only changes the display unit of the same energy. Optical power and photon flow rate are not calculated.
Displayed values are floating-point approximations. Measurement uncertainty and design safety factors are not calculated.
Formula references and credits
NaNa Lab created the code, descriptions, icons and preview images. Text, figures and code from the linked references have not been reproduced.
Physical constants: NIST / CODATA 2022. The values of μ₀ and ε₀ are measured recommendations, not exact defining constants. Values and precision notes are in the source record.
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