Enter the wavelength of any wave frequency into the calculator to determine the wavenumber.

Wavenumber Formula

The following formula is used to calculate a wave number.

u = 1/λ
  • Where u is the wavenumber
  • λ is the wavelength (m)

To calculate the wavenumber, simply divide 1 by the wavelength.

Wavenumber Definition

A wavenumber is defined as the inverse of the wavelength of some wave. It’s the number of waves per unit of length.

Wave Number Example

How to calculate wave number?

  1. First, determine the wavelength.

    Using the velocity and the frequency, determine the wavelength of the wave being analyzed. For this example, we will say the wavelength is 10m.

  2. Next, determine the wave number.

    Using the formula above, we find the wavenumber to be .10 m^-1. This can be described as .10 waves per meter.


What is a wavenumber?

Wavenumber is the unit of frequency used in spectroscopy which is equal to the true frequency divided by the speed of light. In other words, the wave number can be thought of as the number of waves per unit distance.

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wavenumber formula