ToolsSound, propagation & hearing
Speed of sound in air
Speed of sound from temperature, humidity and air pressure.
°C
%
kPa
Sea level ≈ 101.3 kPa. Pressure alone has almost no effect.
- Speed of sound (humid air)
- 343.991m/s
- Speed of sound (dry air, simple formula)
- 343.215m/s
- Speed of sound (humid air)
- 1238.37km/h
- Travel time per metre
- 2.90705ms
- Temperature in Fahrenheit
- 68°F
- Temperature in kelvin
- 293.15K
Humid-air values use Cramer's equation (as implemented by the UK National Physical Laboratory, 400 ppm CO₂). Temperature matters most: about +0.6 m/s per °C; humidity adds up to about 1 m/s at room temperature.
How it works
The speed of sound in air depends almost entirely on temperature. Humidity raises it slightly because water vapour is lighter than air. Air pressure on its own has nearly no effect.
Formulas
- dry air: c ≈ 331.3 · √(1 + T / 273.15)
- humid air: Cramer (1993)
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