Sound Wavelength Calculator

Sound waves propagate as longitudinal pressure oscillations through a medium. The relationship between wavelength, frequency, and wave speed is given by the fundamental wave equation:

$$\lambda = \frac{v}{f}$$

where $$\lambda$$ is the wavelength in meters, $$v$$ is the speed of sound in the medium (default 343 m/s for air at 20°C), and $$f$$ is the frequency in Hz.

The period of the wave — the time for one complete oscillation — is the reciprocal of frequency:

$$T = \frac{1}{f}$$

In air at room temperature, audible frequencies (20 Hz to 20,000 Hz) correspond to wavelengths from about 17 meters down to 1.7 centimeters. Low bass notes have wavelengths comparable to room dimensions, which is why bass frequencies are difficult to control acoustically. High-frequency sounds have wavelengths comparable to small objects, making them easy to reflect and absorb.

The speed of sound varies by medium: approximately 343 m/s in air at 20°C, 1,480 m/s in water, and 5,960 m/s in steel. Adjusting the velocity input allows calculation of wavelengths in different materials.

The concert pitch A4 (440 Hz) has a wavelength of about 0.78 m in air. Human speech fundamental frequencies (85–255 Hz) produce wavelengths of 1.3–4 meters. Wavelengths much larger than an obstacle cause diffraction (sound bends around it), while wavelengths much smaller than an obstacle cause reflection. This is why you can hear someone around a corner (low frequencies diffract) but high-pitched sounds are more directional.