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Wavelength calculator
Find the wavelength of a wave from its frequency and speed, for example radio or light waves.
Wavelength Calculator
λ = c / f · Speed of Light · Frequency
λ = c / f | Wavelength in Meters
Wavelength is the distance between one crest of a wave and the next, and it is locked to frequency by the wave's speed: faster oscillation means shorter waves for the same speed. This calculator moves between wavelength, frequency and speed for any kind of wave.
How to use this calculator
- Enter the wave speed (or pick a preset: sound in air, light in vacuum).
- Enter the frequency to get the wavelength, or the wavelength to get the frequency.
- Press calculate to see the result.
One formula, wildly different scales
The same λ = v/f spans radio waves metres long, visible light measured in billionths of a metre, and ocean swells longer than a ship. Frequency is usually the quantity engineers choose and antennas are then built to the wavelength that results, which is why radio antennas have the sizes they do.
Frequently asked questions
What is the wavelength formula?
λ = v / f: wavelength = wave speed divided by frequency. Frequency follows as f = v / λ.
What is the wavelength of FM radio?
FM broadcasts around 100 MHz; with light's speed that gives a wavelength of about 3 metres, which is why FM antennas are roughly metre-scale.
Does wavelength change between air and water?
For sound, yes: speed changes with the medium while frequency stays fixed, so wavelength stretches or shrinks. For light entering water or glass the same principle applies.