MotionLab

Wavelength Calculator

The distance between wave peaks, from how fast the wave travels and how often it oscillates.

Wave speed (m/s)

Frequency (Hz)

Wavelength (m)

0.78

λ = v / f

What you entered

Wave speed (m/s): 343Frequency (Hz): 440

1
λ = v ÷ f
343 ÷ 440= 0.7795 m

Result

Wavelength (m): 0.78

A 440 Hz wave traveling at 343 m/s has a wavelength of 0.78 m.

Wavelength from wave speed and frequency

Wavelength is wave speed divided by frequency. Sound rows use 343 m/s in air; light rows use 3e8 m/s.

Wave speed (m/s)	Frequency (Hz)	Wavelength (m)	Wave
343	20	17.1500	Lowest audible sound
343	440	0.7795	Concert A
343	20000	0.0171	Highest audible sound
300000000	100000000	3.0000	FM radio, 100 MHz
300000000	2400000000	0.1250	Wi-Fi, 2.4 GHz

The first three rows span human hearing and show why bass is hard to contain: a 20 Hz wave is over 17 m long, far bigger than any room, which is why low frequencies pass through walls while treble does not. The Wi-Fi row at 12.5 cm explains antenna sizes, since efficient antennas are a simple fraction of a wavelength - typically a quarter, so about 3 cm here. Wave speed depends on the medium, so the same frequency has a different wavelength in water or steel than in air.

Same formula, any kind of wave

This relationship holds for sound waves, light waves, water waves — any wave phenomenon — as long as you use the correct wave speed for that medium (343 m/s for sound in air, ~3×10⁸ m/s for light in a vacuum, etc.).

Why bass notes need bigger speakers

Low-frequency (bass) sounds have long wavelengths, and efficiently producing long wavelengths generally requires a larger speaker cone — this is part of why subwoofers are physically bigger than tweeters.

Frequently asked questions

An FM radio station broadcasts at 98.5 MHz. What's the wavelength of that signal?

λ = v/f = 3×10⁸ / 98.5×10⁶ = 3.05 m. That's about 10 feet — which is why FM antennas are roughly that long. AM radio at 1000 kHz has λ = 300 m, needing much larger antenna towers.

Middle C on a piano has a frequency of 261.6 Hz. What's its wavelength in air?

λ = v/f = 343/261.6 = 1.31 m. The highest piano note (~4186 Hz) has λ = 0.082 m (8.2 cm), and the lowest (~27.5 Hz) has λ = 12.5 m. This range of wavelengths is why piano soundboards are the size they are.

How is wavelength related to frequency?

They're inversely proportional at a fixed wave speed: λ = v/f. Double the frequency, halve the wavelength. For light in a vacuum (v = c), this means UV light has shorter wavelengths than red light. See the frequency calculator for the inverse calculation.

Does wavelength change when a wave enters a different medium?

Yes — when light enters glass (slower speed), the frequency stays the same but the wavelength shortens proportionally. This wavelength change is what causes refraction (bending). See Snell's law calculator for the angle calculation.