Speed of Sound Calculator

Speed of Sound in Air

The speed of sound in an ideal gas depends on temperature and the ratio of specific heats. For dry air near sea level:

where \(\gamma \approx 1.4\), \(R = 8.314\ \text{J/(mol·K)}\), \(T\) is absolute temperature in kelvin, and \(M \approx 0.02896\ \text{kg/mol}\) is the molar mass of dry air. Humidity lowers the effective molar mass slightly, increasing the speed of sound.

At 20 °C, \(v \approx 343\) m/s. The Mach number is the ratio of an object's velocity to the local speed of sound: \(\text{Ma} = v_{\text{object}} / v_{\text{sound}}\).