Frequency ↔ Wavelength Calculator
Bi-directional conversion between radio frequency and wavelength using the speed of light in free space.
Tool
How it works
The relationship between frequency (f) and wavelength (λ) in free space is λ = c / f, where c is the speed of light (≈ 299,792,458 m/s). Multiply or divide by the appropriate unit factors (1 kHz = 10³ Hz, 1 MHz = 10⁶ Hz, 1 GHz = 10⁹ Hz) to switch units. Wavelength shortens when the wave travels through a medium with a velocity factor less than 1.
How to use
- Enter a frequency value in the left input and pick its unit.
- Read the resulting wavelength on the right; change the wavelength unit as needed.
- You can also enter a wavelength to solve for frequency — the last edited field drives the calculation.
- For velocity-factor adjustments (coax, wire in insulation), multiply the free-space wavelength by the velocity factor.
Frequently asked questions
Why does the calculator use c = 299,792,458 m/s?
That is the exact defined speed of light in vacuum. In real antenna elements, a velocity factor (typically 0.95–0.98 for bare wire) shortens the practical length.
Can I use this for audio frequencies?
Yes, but wavelengths become very long (a 1 kHz radio wave is ~300 km). It is intended for radio work.
What is the free-space wavelength of 146 MHz?
≈ 2.053 m — the classic 2-meter band.