The calculator presented here computes the zero-frequency speed of sound in humid air according to Cramer (J. Acoust. Soc. Am., 93, p2510, 1993), with saturation vapour pressure taken from Davis, Metrologia, 29, p67, 1992, and a mole fraction of carbon dioxide of 0.0004.

Range of validity: the calculator is only valid over the temperature range 0 to 30 ° C (273.15 - 303.15 K) and for the pressure range 75 - 102 kPa

Temperature    (Celsius)
Pressure    (kPa)
Relative Humidity    (%)
Speed of sound    (m/s)

The model uses JavaScript and therefore only works if your browser is JavaScript enabled. This software has not been subjected to NPL's Quality Assurance procedures. No warranty or guarantee applies to this software, and therefore any users should satisfy themselves that it meets their requirements.

Please note that NPL no longer carries out work in airborne acoustics, so we are unable to answer technical queries.

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