Speed of Sound Calculator

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Are you aware you can measure the speed of sound in water and air, or that temperature sets the speed of sound? The air temperature is high, sound will spread more quickly. Calculating the speed of sound is simpler than you think. Use our speed of sound formulas below, or try out the calculator.

Calculating the Speed of Sound in Air

If you want to know the speed of sound in a gas such as air, use this unique formula. 

c = √ (γ x R x T / M)

c = the speed of sound in an ideal gas
R = the molar gas constant (set at approximately 8.313,5 J) 
γ  = Adiabatic index (1.4 for air) 
T = absolute temperature
M – the gas molar mass (dry air is 0.028,964,5 kg/mol) 

When you are calculating the speed of sound in air, you can simplify the formula to: 

c_air = 331.3 x √ (1 + T/273.15) [m/s]

You may think air’s humidity would be a factor, but this formula shows that is not the case. The two constants in the speed of sound are the adiabatic index (γ) and the molar gas (M). The effect of humidity is too small to be a significant influence.

Calculating the Speed of Sound in Water

There is no easy or accurate way of calculating the speed of sound in water. The most common value is 1,482 m/s for a temperature of 20 degrees-Celsius. That method comes from experimental data and water charts. 

In sonar research and acoustical oceanography, the speed of sound in water is crucial. But it’s everchanging, making it complex data to acquire. With seawater, there are other parameters, including how speed changes with salt.

Learn How to Use a Speed of Sound Calculator

Let’s say you want to find out how sound travels in icy cold water. You could tackle the complexities of a formula yourself, or you could use a speed of sound calculator. Such a tool takes care of the hard work for you. 

1.	Choose the calculation method – water or air. We want to know about sound movement in icy cold water. 
2.	Pick the temperature unit you prefer – Fahrenheit or Celsius. We’ll use Fahrenheit. 
3.	Select the temperature. We’ll say the water is 32 degrees-Fahrenheit. 
4.	The calculator does all the rest. The speed of sound in icy cold water is 1,403 m/s.

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