How this calculation works
The Speed of Sound Calculator computes acoustic propagation velocity through air based on dry air temperature, compares sound speeds across liquid and solid mediums, and calculates Mach 1 velocity.
Mathematical formula and logic
Speed in Dry Air: c = 331.3 × √(1 + (Temp_C / 273.15)) m/s ≈ 331.3 + (0.606 × Temp_C) m/s.
Worked example
In dry air at 20°C (68°F), the speed of sound is 343.4 m/s (1,236.3 km/h = 768.2 mph). Mach 1 equals 343.4 m/s. Sound travels through steel at 5,960 m/s (over 17 times faster than in air).
Calculation assumptions
- Ideal gas adiabatic acoustic wave propagation.
- Dry air with standard heat capacity ratio γ = 1.402.
Frequently asked questions
What is the speed of sound at standard sea level (20°C)?
At 20°C (68°F) at sea level, the speed of sound in dry air is exactly 343.4 meters per second (1,236.3 km/h or 768.2 mph).
Does air pressure affect the speed of sound?
Surprisingly, no! In an ideal gas, density and pressure are directly proportional. When altitude changes, only *temperature* alters the speed of sound in air.
Why does sound travel faster in water and steel than in air?
Liquids and solid metals have vastly higher elastic moduli (stiffness and molecular bonding) than compressible gases, allowing acoustic mechanical vibrations to transfer rapidly between adjacent molecules.
How far away is a lightning strike if thunder takes 5 seconds to hear?
Sound travels ~1 kilometer every 3 seconds (or 1 mile every 5 seconds). If thunder arrives 5 seconds after a lightning flash, the storm is approximately 1.7 kilometers (1.0 mile) away.
What is a sonic boom?
When an aircraft exceeds the speed of sound (Mach 1), it overtakes its own acoustic pressure waves, creating a concentrated conical shock wave heard on the ground as a loud sonic boom.