Photon conversion · Vacuum

Photon energy, wavelength & frequency

Enter any one quantity and the other two update immediately. The conversion uses the exact SI values of the Planck constant and the speed of light.

Convert one photon

All values must be positive. Wavelength means vacuum wavelength; frequency is unchanged when light enters a material.

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Photon energy

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per photon

Wavelength

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in vacuum

Frequency

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cycles per second

Position in the electromagnetic spectrum

Logarithmic wavelength scale. Region boundaries are conventional and approximate.

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Definitions & conversion

Symbols: E = photon energy, ν = frequency, λ = vacuum wavelength.

1 · Fundamental relation

A photon’s energy is proportional to frequency and inversely proportional to wavelength:

Equivalently, ν = c/λ. These expressions use vacuum wavelength.

2 · Exact SI constants

h6.626 070 15 × 10−34 J·sPlanck constant
c299 792 458 m/sspeed of light in vacuum
1 eV1.602 176 634 × 10−19 Jelectronvolt

3 · Useful laboratory forms

The calculator retains full double-precision values internally and rounds only for display.