Speed of Sound - Online Calculator (original) (raw)

The speed of sound in air (or in other gases) can be expressed as

c = (k p / ρ)1/2

= (k R T)1/2 (1)

where

c = speed of sound (m/s, ft/s)

k = ratio of specific heats (adiabatic index, isentropic expansion factor)

p = pressure (Pa, psi)

R = 286.9 (J/kg K) = 1,716 (ft lb/slug oR) = individual gas constant specific for air

T = absolute temperature (K, R)

The calculators below can be used to estimate the speed of sound in air at temperatures close to 273.15 K (0 oC, 31 oF).

Speed of Sound - SI Units

Speed of Sound - Imperial Units

Example - Speed of Sound in Air

The individual gas constant for air is 286.9 J/kgK and the ratio of specific heat is 1.4. The speed of sound at 0 oC (273.15 K) can be calculated as

c = (1.4 (286.9 J/kgK) (273.15 K))1/2

= 331.2 m/s