Frequency to Wavelength Converter
Our free signal & frequency converter handles frequency wavelength conversions. See tables, ratios, and examples for quick reference.
Reviewed by Manoj Kumar, Mathematics Educator
Formula
Wavelength (lambda) = Speed of wave (v) / Frequency (f)
Divide the speed of the wave by its frequency. In vacuum, the speed is 299,792,458 m/s. In other media, divide the vacuum speed by the refractive index. Wave number is the reciprocal of wavelength.
Worked Examples
Example 1: FM Radio Station Wavelength
Problem:What is the wavelength of a 100 MHz FM radio signal in air?
Solution:Wavelength = speed of light / frequency\nlambda = 299,792,458 / 100,000,000\nlambda = 2.998 meters
Result:100 MHz = 2.998 m wavelength (Radio Wave band)
Example 2: 5G Cellular Wavelength
Problem:Calculate the wavelength of a 28 GHz 5G mmWave signal.
Solution:Wavelength = 299,792,458 / (28 * 10^9)\nlambda = 299,792,458 / 28,000,000,000\nlambda = 0.01071 meters = 10.71 mm
Result:28 GHz = 10.71 mm wavelength (Microwave band)
Frequently Asked Questions
How do you convert frequency to wavelength?
Wavelength equals the speed of the wave divided by its frequency, expressed as lambda = v / f. For electromagnetic waves in a vacuum, v is the speed of light (299,792,458 m/s). For example, an FM radio station at 100 MHz has a wavelength of 299,792,458 / 100,000,000 = 2.998 meters. In other media like water or glass, the speed is reduced by the refractive index, producing shorter wavelengths.
Does wavelength change in different media?
Yes, wavelength changes when a wave enters a different medium because the wave speed changes while the frequency stays constant. The speed in a medium equals the speed of light divided by the refractive index (n). For example, light in glass (n = 1.5) travels at 2/3 the speed of light, so its wavelength is also 2/3 of what it would be in vacuum. This principle is fundamental to optics, fiber communications, and lens design.
References
Reviewed by Manoj Kumar, Mathematics Educator · Editorial policy