Wavelength & Frequency Calculator
Convert between wavelength and frequency and get the photon energy.
Wavelength
—
Frequency
—
Photon energy
—
Period
—
Spectrum band
—
Results update as you type.
About this calculator
For a wave, speed = wavelength × frequency, so λ = c / f with the speed of light c = 299,792,458 m/s in a vacuum. This calculator converts either way and also gives the photon energy E = h × f using Planck’s constant h = 6.62607015 × 10⁻³⁴ J·s.
Frequently asked questions
How are wavelength and frequency related?
They are inversely related through the wave speed: λ = c / f. A higher frequency means a shorter wavelength, since their product is the constant speed of light.
How is photon energy calculated?
A photon’s energy is E = h × f, where h = 6.62607015 × 10⁻³⁴ J·s. Higher-frequency light (blue, UV) carries more energy per photon than lower-frequency light.
Results are estimates for general guidance only, not financial, medical or tax advice.