Frequency ↔ Wavelength Calculator
Convert between frequency and wavelength for radio, light and sound waves — plus photon energy for electromagnetic waves.
How to use
- 1Choose electromagnetic (radio, light) or sound.
- 2Enter a frequency (Hz) or a wavelength (m) and leave the other blank.
How it's calculated
λ = v ÷ f, where v = 299,792,458 m/s for electromagnetic waves or ~343 m/s for sound in air. Photon energy E = h f.
Frequently asked questions
What wavelength is 2.4 GHz Wi-Fi?
About 12.5 cm — the speed of light divided by 2.4 billion cycles per second.
What's the wavelength of green light?
Around 530 nm, which is a frequency of about 566 THz.
Why do antennas relate to wavelength?
Efficient antennas are usually a fraction of the wavelength — a half-wave dipole for 100 MHz FM is about 1.5 m long.