🔊 Speed of Sound Calculator
Calculate the speed of sound in gases, liquids, and solids. Choose a medium or enter custom properties like density, bulk modulus, and temperature. Includes Mach number conversion and common reference values.
What Is the Speed of Sound?
The speed of sound is the distance traveled per unit time by a sound wave as it propagates through an elastic medium. It is determined by the medium's density and elasticity, and varies with temperature, pressure, and composition.
Key facts about the speed of sound:
- In air at 20°C: ~343 m/s (1,235 km/h, 767 mph).
- In water at 20°C: ~1,482 m/s (5,335 km/h).
- In steel: ~5,960 m/s (21,456 km/h).
- In a vacuum: Sound cannot travel — no medium to vibrate.
The speed of sound increases with temperature in gases, but decreases with temperature in some liquids. In solids, it depends on the material's stiffness (Young's modulus) and density.
Formulas for the Speed of Sound
The formula depends on the medium:
Gases: c = √(γRT/M)
Liquids: c = √(K/ρ)
Solids: c = √(E/ρ)
Where:
- c = speed of sound (m/s)
- γ = adiabatic index (1.4 for air)
- R = specific gas constant (J/kg·K)
- T = absolute temperature (K)
- M = molar mass (kg/mol)
- K = bulk modulus (Pa)
- ρ = density (kg/m³)
- E = Young's modulus (Pa)
Mach Number
The Mach number is the ratio of an object's speed to the speed of sound in the surrounding medium. Mach 1 is the speed of sound; Mach 2 is twice the speed of sound. At sea level, Mach 1 is approximately 340 m/s (1,225 km/h, 761 mph).
Why Use This Calculator?
- Multiple media: Calculate speed in gases, liquids, and solids.
- Preset media: Choose from common media like air, water, steel, and more.
- Step-by-step breakdown: See exactly how the calculation is performed.
- Free & private: No registration, no data storage — all calculations are done in your browser.
❓ Speed of Sound Calculator FAQ
What is the speed of sound in air?
At 20°C (68°F), the speed of sound in air is approximately 343 m/s (1,235 km/h or 767 mph). At 0°C, it is about 331 m/s.
What is the formula for the speed of sound in a gas?
The formula is c = √(γRT/M), where γ is the adiabatic index, R is the specific gas constant, T is the absolute temperature, and M is the molar mass.
What is the formula for the speed of sound in a liquid?
The formula is c = √(K/ρ), where K is the bulk modulus and ρ is the density of the liquid.
What is the formula for the speed of sound in a solid?
The formula is c = √(E/ρ), where E is Young's modulus and ρ is the density of the solid.
How does temperature affect the speed of sound?
In gases, the speed of sound is proportional to the square root of the absolute temperature. For every 1°C increase, the speed of sound in air increases by about 0.6 m/s.
What is the Mach number?
The Mach number is the ratio of an object's speed to the speed of sound in the surrounding medium. Mach 1 is the speed of sound; Mach 2 is twice the speed of sound.
Does sound travel faster in water or air?
Sound travels much faster in water (~1,482 m/s) than in air (~343 m/s) because water is much less compressible (higher bulk modulus) and denser.
Can sound travel through a vacuum?
No. Sound requires a medium (gas, liquid, or solid) to propagate. In a vacuum, there are no particles to vibrate, so sound cannot travel.
How accurate is this calculator?
This calculator uses standard formulas and typical material properties. Actual values may vary with temperature, pressure, composition, and material purity.
Is this calculator free?
Yes, this calculator is completely free to use. No registration or personal data storage is required.