Frequency Wavelength Converter

Frequency and wavelength are two ways of describing the same electromagnetic wave — how many oscillations occur per second (frequency, in hertz) and the physical distance between successive wave peaks (wavelength, in meters). The two are inversely linked through the speed of light: multiply frequency by wavelength and you always get 299,792,458 meters per second, the universal speed at which all electromagnetic radiation travels through a vacuum.

Our Frequency Wavelength converter supports hertz (Hz), the SI unit of frequency, along with the complete metric prefix range — exahertz, petahertz, terahertz, gigahertz, megahertz, kilohertz, hectohertz, dekahertz, decihertz, centihertz, millihertz, microhertz, nanohertz, picohertz, femtohertz, and attohertz — plus cycle/second, which is numerically identical to hertz. Alongside these frequency units, the converter includes equivalent wavelength units expressed in meters and their metric prefixes (from exametres down through the standard length scale), letting you convert directly between "how fast it oscillates" and "how long each wave is."

To use the converter, select your starting and target units from the dropdown lists and enter a value — the result is calculated instantly to up to 12 significant digits. For example, converting a 100 megahertz FM radio frequency to wavelength gives almost exactly 3 meters, and converting visible light's frequency of roughly 500 terahertz gives a wavelength of about 600 nanometers, in the orange-yellow part of the visible spectrum.

Frequency-wavelength conversion is fundamental to understanding the electromagnetic spectrum, which spans from long-wavelength, low-frequency radio waves (used for broadcasting and communication) through microwaves, infrared, the narrow band of visible light (roughly 400-790 THz, or 380-750 nm), ultraviolet, X-rays, and finally extremely short-wavelength, high-frequency gamma rays. Radio and telecommunications engineers use wavelength to size antennas (an antenna's optimal length is typically a fraction of the signal's wavelength), physicists and chemists use frequency-wavelength relationships in spectroscopy to identify substances by the specific wavelengths of light they absorb or emit, and optics engineers design lenses and coatings tuned to specific wavelength ranges.

All conversion factors used in this tool are based on the exact, defined speed of light in a vacuum and precise metric prefix relationships, so results are dependable for physics coursework, telecommunications engineering, and spectroscopy work. The converter is free, requires no account, and works equally well on desktop and mobile devices.

Because the speed of light is a fixed universal constant, frequency and wavelength conversions here are exact rather than approximate — a useful property when cross-checking a spectroscopy result, verifying a radio antenna's design wavelength, or confirming where a given light source falls within the visible or invisible portions of the electromagnetic spectrum.