Speed of Sound in a Medium Calculator

About this calculator

The speed of sound in a medium depends on how stiff and how dense that material is: v = √(K/ρ), where K is the elastic (bulk) modulus and ρ is the density. Stiffer materials transmit pressure disturbances faster because their particles snap back into place more quickly, which is why sound travels only about 343 m/s in air but roughly 1,480 m/s in water and around 5,000–6,000 m/s in steel — despite steel being far denser, its bulk modulus is proportionally even higher.

This same relationship (using Young's modulus E instead of K for a thin solid rod) is the basis for ultrasonic thickness testing, sonar depth-finding, and seismic surveying, where the travel time of a sound or shock wave reveals properties of the material it passed through. Acoustic and materials engineers, geophysicists doing seismic surveys, and non-destructive testing technicians use this formula to predict sound speed in a new material or to work backward from a measured speed to infer a material's stiffness or density.