# Frequency-Wavelength Calculator

### Use the Frequency-Wavelength Calculator to calculate the frequency from the wavelength, or the wavelength from the frequency

Any repetitive or cyclic behaviour can be represented by a cycle. The number of cycles completed in one second is called the frequency.

Radio waves travel at the speed of light in a vacuum. If an R.F. current has a frequency of 780,000 cycles per second, the wave will go through one complete cycle in 1/780,000 second. In that same period of time the wave will move 299,792,458/780,000 = 384.349 metres. By the time the wave has moved that distance the next cycle has begun and a new wave has started its journey. The first wave, representing one cycle, covers a distance of 384.349 metres before the beginning of the next. This distance is the wavelength.

The formula for calculating the frequency from the wavelength is:

$F= \frac{c}{\lambda }$

The formula for calculating the wavelength from the frequency is:

$\lambda =\frac{c}{F}$

Where
F = Frequency in Cycles per second (C.P.S.) or Hertz (Hz)
c = 299,792,458 = Speed of light in metres per second
λ = Wavelength in metres

Example 1: The frequency corresponding to a wavelength of 80 metres is

$F= \frac{299,792,458}{80}=3,747,406\; Cycles/sec$

Example 2: The wavelength corresponding to a frequency of 780 kc is

$\lambda =\frac{299,792,458}{780,000}=384.349\; Metres$

### Using the Frequency-Wavelength Calculator

Calculating the wavelength: Enter the frequency into the green frequency cell and select the appropriate units. The calculated wavelength is displayed in the red cell with the option to select the units.

Calculating the frequency: Enter the wavelength into the green wavelength cell and select the appropriate units. The calculated frequency is displayed in the red cell with the option to select the units.

Selecting units: You can choose your preferred units of measurement through selecting the units cells and clicking the arrow to display a list of available options

Reference: ARRL – The Radio Amateur’s Handbook

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