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Frequency and Wavelength Converter

Convert between frequency (Hz, kHz, MHz, GHz) and wavelength (m, cm, mm). Pick a propagation speed such as light or sound and instantly compute λ = v / f.

Input

Frequency unit
Wave speed (medium)

Result

Wavelength

2.9979m

Wave speed v = 299,792,458 m/s (λ = v / f)

Frequency

UnitSymbolValue
HertzHz100,000,000
KilohertzkHz100,000
MegahertzMHz100
GigahertzGHz0.1

Wavelength

UnitSymbolValue
Meterm2.9979
Centimetercm299.7925
Millimetermm2,997.9246

How it works

  • Wave speed v, frequency f, and wavelength λ are related by v = f × λ, so wavelength is λ = v / f and frequency is f = v / λ.
  • The wave speed defaults to the speed of light in vacuum (299,792,458 m/s), with presets for the speed of sound in air and water plus a custom speed. Use the speed of light for radio and light, and the speed of sound for acoustic waves.
  • Frequency is shown in Hz, kHz, MHz, and GHz, and wavelength in m, cm, and mm at the same time, so you can read off whichever unit is most convenient.
  • For example, a 100 MHz radio wave in vacuum has a wavelength of about 3 m, while 2.4 GHz is about 12.5 cm. This is handy for estimating antenna lengths.
  • Because sound travels far slower than light, an acoustic wave has a much shorter wavelength than a radio wave at the same frequency. Be careful to select the correct medium.
  • Values that are extremely large or small are shown in exponential notation (e.g. 3.0000e+8). Actual propagation speeds vary with temperature and medium, so treat the results as estimates.