Wavelength Calculator

Wavelength from frequency (or the reverse) for sound, light or any wave speed.

Wavelength Calculator

Worked example result

Wavelength	0.779545 m
Frequency	440.0000 Hz
Wave speed used	343.00 m/s

Concert A (440 Hz) has a wavelength of about 0.780 m in air at 20 °C.

Every wave obeys v = f × λ: wave speed equals frequency times wavelength. Give any two of the three quantities and the third follows.

Presets cover sound in dry air at 20 °C (343 m/s) and light in vacuum (c = 299,792,458 m/s exactly), or enter a custom speed — for example about 1,480 m/s for sound in water.

The formula

λ = v ÷ f; f = v ÷ λ

Worked example

Concert A (440 Hz) has a wavelength of about 0.780 m in air at 20 °C.

The example is pre-loaded in the result panel — press Calculate with your own numbers to replace it.

Frequently asked questions

What is the wavelength of FM radio?

FM broadcasts around 100 MHz. With light mode selected, 100,000,000 Hz gives λ ≈ 3.0 m — which is why FM antennas are roughly that scale.

Does the speed of sound change with temperature?

Yes — about 331 m/s at 0 °C, rising roughly 0.6 m/s per degree. This calculator's preset uses the standard 343 m/s at 20 °C; use a custom speed for other temperatures.

Category: Science calculators

Wavelength Calculator