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Frequency to Wavelength Calculator

Convert between frequency and wavelength using λ = v / f. Defaults to the speed of light (for electromagnetic waves) but you can set any wave speed for sound or other waves.

 

Formula

$$ v = f\,\lambda \qquad \lambda = \frac{v}{f} \qquad f = \frac{v}{\lambda} $$
For light in vacuum, v = c = 299,792,458 m/s

Worked example

Green light at 5×10¹⁴ Hz has wavelength \( \lambda = c/f = (3\times10^{8})/(5\times10^{14}) = 6\times10^{-7}\ \text{m} = 600\ \text{nm} \), right in the middle of the visible spectrum.

How it works

Every wave satisfies v = fλ, so frequency and wavelength are inversely related for a fixed speed: higher frequency means shorter wavelength. For light and other electromagnetic waves, v is the speed of light c.

Set the wave speed (it defaults to c) and enter either frequency or wavelength to get the other. This is the standard conversion for photons, radio waves and the electromagnetic spectrum, and works for sound too if you set v to the speed of sound.

Frequently asked questions

How do you convert frequency to wavelength?

Divide the wave speed by the frequency: λ = v/f. For light, use v = c = 3×10⁸ m/s, so a 5×10¹⁴ Hz wave is 600 nm.

What is the formula linking frequency and wavelength?

v = f λ, so f = v/λ and λ = v/f. For electromagnetic waves in vacuum, v is the speed of light.

Does higher frequency mean shorter wavelength?

Yes. At a fixed wave speed, frequency and wavelength are inversely proportional, so doubling the frequency halves the wavelength.

What speed should I use for light versus sound?

Use c = 299,792,458 m/s for light and other electromagnetic waves in vacuum, and about 343 m/s for sound in air at room temperature.

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