Wavelength Calculator

Work out wavelength, frequency or wave speed with the formula v = f × λ. Fill in two of the three fields and leave the third at 0, and the calculator works out the rest.

Wavelength
0.77 m
Calculated from wave speed and frequency
Wave speed
340 m/s
Frequency
440 Hz
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How to use the wavelength calculator

  1. Enter the two values you know: wave speed, frequency or wavelength.
  2. Leave the field you don't know at 0 — the calculator automatically works out that value.
  3. If you fill in all three fields, the calculator instead checks whether they're actually consistent.

The relationship between wavelength, frequency and speed

v = f × λ

Wave speed (v) equals frequency (f) multiplied by wavelength (λ). The formula applies to all types of waves — sound waves, light waves and water waves — as long as the speed stays constant in the medium the wave travels through.

Sound in air has a speed of about 340 m/s, while light travels enormously faster, at about 3 × 10⁸ m/s in a vacuum. That's why lightning is seen long before thunder is heard, even though both occur at the same time.

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Frequently asked questions

What's the relationship between wavelength and frequency?

Wavelength and frequency are inversely proportional when speed is constant: the higher the frequency, the shorter the wavelength, and vice versa. The relationship is described by the formula v = f × λ, where v (the speed) stays fixed for a given medium.

Why is the speed of sound different in air and water?

The speed of sound depends on how tightly packed the molecules in the medium are and how quickly they can transfer vibrations to each other. Water is far denser than air, so sound travels much faster in water (about 1,480 m/s) than in air (about 340 m/s).

Can I use this for light waves too?

Yes, the formula v = f × λ also applies to light, but then you need to use the speed of light (about 3 × 10⁸ m/s in a vacuum) as the wave speed instead of the speed of sound. Light's wavelengths are in turn far shorter than sound's.

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