Wavelength Calculator

Convert between frequency and wavelength with an optional velocity factor, and get the half-wave and quarter-wave lengths.

Leave one of frequency or wavelength blank to solve for it. Velocity factor is 1 for free space, ~0.66 for typical coax.
Solved value
Wavelength λ
Half-wave (λ/2)
Quarter-wave (λ/4)
Wave speed

Frequency and wavelength

A wave's wavelength is the distance it travels in one cycle: the wave speed divided by its frequency. In free space electromagnetic waves travel at the speed of light, c ≈ 299 792 458 m/s.

λ = v / f, where v = c × velocity factor

The velocity factor accounts for waves travelling slower than light through a cable or antenna element — around 0.66 for common coax and 0.95–0.98 for bare antenna wire. The half-wave and quarter-wave figures are handy starting points for antenna element lengths.

Related

For circuit resonance rather than physical wavelength, see theLC resonant frequency andreactance calculators.