Wavelength & Frequency Calculator
Wavelength from frequency and back, for light, sound, or any wave speed.
One formula, every wave
λ = v / f
Wavelength times frequency always equals the wave speed. FM radio at 100 MHz has 3-meter waves (and antennas sized in fractions of that). Concert-pitch A at 440 Hz in air is 78 cm long. WiFi at 2.4 GHz is 12.5 cm, which is why a microwave oven, at the same band, has a mesh door with holes far smaller than that.
Same wave, different medium
Frequency is fixed by the source; the wavelength stretches or shrinks with the medium's speed. Sound jumps from 343 m/s in air to 1,481 m/s in water, so the same tone is over four times longer under the surface, one reason echolocation and sonar live at high frequencies.