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}

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

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

Learn As You Go: This feature displays a live example of how to perform the calculation using the figures that you enter

Reference: ARRL – The Radio Amateur’s Handbook