Wavelength, Frequency & Photon Energy Converter
Convert light and other electromagnetic radiation between wavelength (nm, µm, Å), frequency (Hz, THz), photon energy (eV, J, kJ/mol) and wavenumber (cm⁻¹).
1 hertz = 4.1356677 × 10-15 electronvolts (photon energy)
Most used spectrum units
- Nanometer (wavelength) nm 1 nm = 2.9979246 × 1017 Hz
- Electronvolt (photon energy) eV 1 eV = 241,798,920,000,000 Hz
- Terahertz THz 1 THz = 1,000,000,000,000 Hz
- Gigahertz GHz 1 GHz = 1,000,000,000 Hz
- Wavenumber cm⁻¹ 1 cm⁻¹ = 29,979,246,000 Hz
- Micrometer (wavelength) µm 1 µm = 299,792,460,000,000 Hz
- Hertz Hz Base unit
- Megahertz MHz 1 MHz = 1,000,000 Hz
- Kiloelectronvolt (photon energy) keV 1 keV = 2.4179892 × 1017 Hz
- ångström (wavelength) Å 1 Å = 2.9979246 × 1018 Hz
- Joule (photon energy) J 1 J = 1.5091902 × 1033 Hz
- Meter (wavelength) m 1 m = 299,792,460 Hz
Popular spectrum conversions
- Nanometers (wavelength) to electronvolts (photon energy)
- Electronvolts (photon energy) to nanometers (wavelength)
- Nanometers (wavelength) to terahertz
- Terahertz to nanometers (wavelength)
- Wavenumbers to nanometers (wavelength)
- Nanometers (wavelength) to wavenumbers
- Micrometers (wavelength) to wavenumbers
What is spectrum?
Light, radio waves, X-rays and all other electromagnetic radiation can be described by three linked quantities: wavelength λ, frequency f and photon energy E. They are tied together by the speed of light and the Planck constant: c = λ·f and E = h·f. So wavelength and frequency are reciprocal (shorter waves have higher frequencies), while energy is proportional to frequency.
A handy shortcut: photon energy in electronvolts ≈ 1239.84 ÷ wavelength in nanometers. Green light at 532 nm has photons of about 2.33 eV.
Spectroscopists also use the wavenumber, waves per centimeter (cm⁻¹), which is proportional to energy.
All 20 spectrum units
Wavelength
- Centimeters (wavelength)
- Meters (wavelength)
- Micrometers (wavelength)
- Millimeters (wavelength)
- Nanometers (wavelength)
- Picometers (wavelength)
- ångströms (wavelength)
Frequency
Photon energy
- Electronvolts (photon energy)
- Joules (photon energy)
- Kelvins (temperature equivalent)
- Kiloelectronvolts (photon energy)
- Kilojoules per mole (photon energy)
- Millielectronvolts (photon energy)
Wavenumber & period
Frequently asked questions
How do I convert nm to eV?
Divide 1239.84 by the wavelength in nm: 500 nm ≈ 2.48 eV.
How do I convert wavelength to frequency?
Divide the speed of light (299,792,458 m/s) by the wavelength in meters: 500 nm ≈ 599.6 THz.