Frequency to Wavelength Calculator
Enter a frequency in Hz, kHz, MHz, GHz, or THz to instantly get the wavelength of that electromagnetic wave in metres, centimetres and nanometres, plus the period and angular frequency.
Frequency unit
λ = c / f — speed of light divided by frequency
- 1
Convert frequency to Hz
100 MHz × 1e+6 = 100,000,000 HzAll unit conversions reduce to Hz before dividing into c. - 2
Wavelength λ = c / f
299 792 458 ÷ 100,000,000 = 2.997925
How does this calculator work?
Every electromagnetic wave obeys λ = c / f, where c = 299 792 458 m/s. Enter your frequency (choose Hz, kHz, MHz, GHz or THz) and get the wavelength in metres and other units, plus the period and angular frequency. Higher frequency always means shorter wavelength.
Formula
How this is calculated
All electromagnetic waves — radio, microwave, infrared, visible light, X-rays, gamma rays — travel at the same speed in a vacuum: c = 299 792 458 m/s (exactly, by the SI definition of the metre). The wavelength λ and frequency f are related by λ = c / f, so a higher frequency means a shorter wavelength and vice versa.
This relationship holds precisely in free space (vacuum). In any material medium the effective speed is c / n where n is the refractive index (greater than 1 for glass, water, etc.), so the wavelength is reduced by that factor even though the frequency stays constant. This calculator assumes propagation in vacuum, which is the standard engineering and physics reference.
The period T = 1/f is the time for one complete oscillation. The angular frequency ω = 2πf (radians per second) is used in wave equations and phasor analysis. For visible light the wavelength falls between roughly 380 nm (violet) and 740 nm (red); radio bands span metres to kilometres.
Frequently asked questions
Yes. In a medium with refractive index n, the wavelength is λ_medium = c / (n·f) = λ_vacuum / n. The frequency stays the same; only the wavelength (and propagation speed) changes. This calculator gives the vacuum wavelength.
Visible light spans roughly 400 THz (red, ~740 nm) to 790 THz (violet, ~380 nm). Enter a frequency in THz and select THz to see where it falls on the spectrum.
The SI metre is defined since 1983 so that c is exactly that value. It is a fixed constant, not a measurement with uncertainty. The wavelength result from this calculator is therefore exact for a given frequency.
Also known as
TG we-Calculate Editorial Team. (2026). Frequency to Wavelength Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/frequency-to-wavelength-calculator
TG we-Calculate Editorial Team. "Frequency to Wavelength Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/frequency-to-wavelength-calculator.
TG we-Calculate Editorial Team, "Frequency to Wavelength Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/frequency-to-wavelength-calculator
@misc{wecalculate_frequency_to_wavelength_calculator, title = {Frequency to Wavelength Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/frequency-to-wavelength-calculator}}, year = {2026}, note = {TG we-Calculate} }
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