What this converter does
This converter turns a wavelength into its frequency and back. The two are inversely related through the wave’s speed: at a fixed velocity, a longer wave means a lower frequency. Enter the propagation speed — the speed of light by default — and read the frequency as you type.
Use the default 3×10⁸ m/s for radio and light in vacuum or air. For a coax or fibre, enter the medium’s slower velocity to get an accurate result.
The units it covers
Wavelength and frequency are inversely linked through the wave’s speed in its medium — light in vacuum, or slower in cable or fibre.
View all units & their values
| Unit | Symbol | Value | Mainly used |
|---|---|---|---|
| Wavelength | m | λ | Physical length of one cycle |
| Frequency | Hz | f | Cycles per second |
| Velocity | m/s | v | Wave speed (c = 3×10⁸ in vacuum) |
The formula
Wavelength equals the propagation speed divided by frequency, so the two are inversely proportional at a given velocity:
λ = v ÷ fWhere:
- λ = wavelength in metres
- f = frequency in hertz
- v = propagation velocity (m/s)
Worked example
Find the frequency of a 1-metre radio wave in air.
f = v ÷ λ299792458 ÷ 1 ≈ 299.8 MHzA 1-metre wavelength corresponds to about 300 MHz in air.
The units in this example
The physical length of one wave cycle. Longer wavelengths mean lower frequencies at the same speed.
- 1 m ≈ 300 MHz (in air)
- 0.125 m ≈ 2.4 GHz (Wi-Fi)
- 3×10⁸ m = 1 Hz
- λ = v ÷ f
Cycles per second. Rises as wavelength shortens for a fixed propagation speed.
- 300 MHz ≈ 1 m
- 2.4 GHz ≈ 0.125 m
- 1 GHz ≈ 0.30 m
- f = v ÷ λ