air absorption calculator

This calculator calculates the speed of sound based on temperature, relative humidity and altitude according to Owen Cramer's paper "The variation of the specific heat ratio and the speed of sound in air with temperature, pressure, humidity, and CO2 concentration" published in the Journal of the Acoustical Society of America.

The calculator is valid for temperatures from 0 - 30 °C (32 - 86 °F) and pressures from 75 - 102 kPa.


  • metric and imperial
  • estimated uncertainty ≤ 300 ppm

file type: Microsoft Excel Open XML spreadsheet (.xlsx)

minimum requirements:

  • Excel 2007 or higher
  • Excel 2008 or higher

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