Frequency-Wavelength Converter
For electromagnetic waves in a vacuum, frequency and wavelength are related by the exact speed of light: c = 299,792,458 m/s. Enter a frequency in any unit to calculate the wavelength, or enter a wavelength to calculate the frequency. This converter handles the full electromagnetic spectrum from extremely low frequency radio waves through visible light and into the X-ray range.
Frequency-wavelength formula
lambda (m) = c / f (Hz) where c = 299,792,458 m/s (exact)
The speed of light c = 299,792,458 m/s is an exact defined constant since 1983 (BIPM/NIST). This applies to electromagnetic radiation in a vacuum. In other media, use the phase velocity v = c/n where n is the refractive index.
Frequency band reference
- 60 Hz: Power line frequency, wavelength 5,000 km.
- 540 to 1,700 kHz: AM radio band, wavelength 176 to 556 m.
- 88 to 108 MHz: FM radio band, wavelength 2.78 to 3.41 m.
- 2.4 GHz / 5 GHz: WiFi bands, wavelengths 12.5 cm / 6.0 cm.
- 430 to 790 THz: Visible light, wavelengths 380 to 700 nm.
Frequency-wavelength converter: frequently asked questions
What is the relationship between frequency and wavelength?
For electromagnetic waves in a vacuum: wavelength = speed of light / frequency, or lambda = c / f. The speed of light is exactly 299,792,458 m/s by NIST definition. So a 100 MHz radio wave has wavelength = 299,792,458 / 100,000,000 = 2.998 m.
What frequency corresponds to visible light?
Visible light spans approximately 380 nm to 700 nm wavelength, corresponding to 430 THz (red) to 790 THz (violet). Wavelength and frequency have an inverse relationship: red light has longer wavelength and lower frequency than violet light.
What wavelength is a 2.4 GHz WiFi signal?
At 2.4 GHz (2,400,000,000 Hz): wavelength = 299,792,458 / 2,400,000,000 = 0.1249 m = 12.49 cm. The 5 GHz WiFi band has wavelength approximately 6 cm. Shorter wavelengths penetrate walls less easily, which is why 5 GHz WiFi has shorter range.
What frequency is AM radio?
AM radio in the US operates from 540 kHz to 1,700 kHz. At 1,000 kHz (1 MHz), the wavelength is 299.79 m. AM radio's long wavelengths enable it to travel long distances by reflecting off the ionosphere, especially at night.
What is the wavelength of a 60 Hz power line?
At 60 Hz: wavelength = 299,792,458 / 60 = 4,996,541 m = approximately 5,000 km. Power line electromagnetic fields are extremely low frequency (ELF). Their wavelengths are so long relative to any antenna size that they cannot radiate efficiently as electromagnetic waves.
Official sources
- NIST CODATA: Speed of light in vacuum (exact value).
- BIPM SI Brochure: Definition of the meter via speed of light.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.