Convert between UV-Vis wavelength, photon energy, frequency, and wavenumber. Enter a value in any unit to see all equivalent values and identify the spectral region (UV-C, UV-B, UV-A, visible color, or near IR).
Enter a wavelength, photon energy, frequency, or wavenumber to convert between common UV-Vis units and see which spectral region it falls into.
E = hc/λ (photon energy)
ν = c/λ (frequency)
ṽ = 1/λ (wavenumber)
This is an educational UV-Vis helper based on simple formulas. It is not a safety calculator or a substitute for instrument calibration.
Ultraviolet and visible (UV-Vis) light spans wavelengths from about 100 nm to 700 nm. This region is important in chemistry because electronic transitions in molecules absorb UV-Vis light, making it useful for spectroscopy and photochemistry.
Photon energy is inversely proportional to wavelength. Shorter wavelengths have higher energy.
Frequency is inversely proportional to wavelength. Shorter wavelengths have higher frequency.
Wavenumber is the reciprocal of wavelength, proportional to energy. Common in IR spectroscopy.
eV (electron-volts): Energy per photon. Convenient for discussing individual photon interactions. Visible light is roughly 1.7–3.1 eV.
kJ/mol: Energy per mole of photons (Avogadro's number of photons). Useful for comparing to bond energies and reaction enthalpies. Visible light is roughly 170–300 kJ/mol.
To convert: E(kJ/mol) = E(eV) × 96.485 kJ·mol⁻¹·eV⁻¹
Measures absorption at different wavelengths to identify compounds and determine concentrations.
Studies chemical reactions initiated by light absorption, requiring specific photon energies.
Band gap measurements in semiconductors relate to UV-Vis absorption edges.
Protein and nucleic acid quantification often uses UV absorbance at 260–280 nm.
Educational Use Only
This tool provides simplified vacuum-based calculations for learning and homework-style spectroscopy context. It does not account for refractive index, spectral width, or instrumental response. Do NOT use for safety exposure limits, laser system design, phototherapy planning, or regulatory compliance. Real UV safety assessments require calibrated measurements and expert guidance.
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