Frequency-Wavelength Calculator

Calculate the frequency from the wavelength, or the wavelength from the frequency with the Frequency-Wavelength Calculator, and learn how with the integrated live example

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: Select Wavelength from the first drop down list, enter the frequency, and select the appropriate units

Calculating the frequency: Select Frequency from the first drop down list, enter the wavelength, and select the appropriate units

How To Calculate Frequency And Wavelength: This feature displays a live example of how to calculate the frequency or the wavelength using the figures that you enter

The result is calculated and updated automatically as you enter different numbers or change between the input fields. If the calculated result hasn’t updated after you’ve finished entering your values, click or tap on the result.

Reference: ARRL – The Radio Amateur’s Handbook