๐ Sound Wavelength Calculator
Speed of sound uses the dry-air formula 331.3 ร โ(1 + temperature รท 273.15).
Enter a frequency (Hz) and air temperature to calculate the sound wave's wavelength, using the standard approximation for the speed of sound in dry air (331.3 + 0.606 ร temperature). Useful as a reference for instrument tuning or acoustic design.
How to use
- Enter a frequency (Hz), or pick one of the preset buttons.
- Enter the air temperature (ยฐC).
- The wavelength and speed of sound are calculated automatically.
How the calculation works
From a frequency and the air temperature, this tool calculates the wavelength of a sound (the length of one wave) in air. Wavelength (m) = speed of sound (m/s) รท frequency (Hz) Speed of sound (m/s) = 331.3 ร โ(1 + temperature รท 273.15) The speed of sound depends on temperature: about 331 m/s at 0ยฐC and about 343 m/s at 20ยฐC. The common shortcut โ331.3 + 0.606 ร temperatureโ gives almost the same value at room temperature, but this tool uses the exact square-root form so it stays right across a wide range. Lower notes have longer wavelengths. Across the audible range of 20 Hz to 20 kHz, wavelengths run from about 17 m down to about 1.7 cm, a thousandfold range.
Worked example
440 Hz (A4) at 20ยฐC Speed about 343.2 m/s โ wavelength about 78.0 cm 100 Hz at 20ยฐC โ about 3.43 m 1000 Hz at 20ยฐC โ about 34.3 cm The same 440 Hz at 0ยฐC: 331.3 รท 440 = about 75.3 cm
Things to be aware of
- In room acoustics, frequencies whose half-wavelengths fit a room dimension a whole number of times tend to boom or resonate (standing waves).
- Humidity raises the speed of sound slightly; this tool assumes dry air.
- Sound travels at about 1500 m/s in water, over four times faster than in air. This tool is for air.
FAQ
What formula is used for the speed of sound?
The speed of sound in dry air is calculated as 331.3 ร โ(1 + temperature (ยฐC) รท 273.15) m/s: about 331.3 m/s at 0ยฐC and about 343.2 m/s at 20ยฐC. Near room temperature it matches the common approximation 331.3 + 0.606 ร temperature.
How is the wavelength calculated?
Wavelength (m) = speed of sound (m/s) รท frequency (Hz) โ the basic relationship between wave speed, frequency, and wavelength.
Why does temperature affect wavelength?
The speed of sound changes with air temperature (higher temperature means faster molecular motion and a higher speed of sound), so for the same frequency, a different temperature gives a different wavelength.