Speed of Sound Calculator

Find how fast sound travels. This free speed of sound calculator computes the speed in air by temperature (°C or °F), or in water, glass and steel, with results in m/s, km/h, mph and Mach 1.

Medium
°C

In air, the speed of sound rises with temperature — about 0.6 m/s for every 1 °C. Pick another medium to use a typical fixed value (sound travels much faster in liquids and solids).

Speed of sound
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Choose a medium
Metres / second
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Km / hour
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Miles / hour
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Mach 1 equals
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For air, this uses v = 331.3 × √(1 + T⁄273.15) with T in °C — the standard dry-air approximation. At 0 °C sound travels about 331 m/s; at 20 °C about 343 m/s.

Use this free speed of sound calculator to find how fast sound travels in air at a given temperature, or in other materials. Results come in m/s, km/h, mph and Mach 1.

What this speed of sound calculator does

A speed of sound calculator finds how fast sound moves through a medium. In air it depends on temperature; in liquids and solids it’s much faster. Mach 1 is simply the local speed of sound.

The speed of sound in air

v = 331.3 × √(1 + T / 273.15) (T in °C)
≈ 331.3 + 0.6 × T (handy approximation)

At 0 °C sound travels about 331 m/s; at 20 °C, about 343 m/s (767 mph).

Speed of sound in different media

Medium Approx. speed
Air (20 °C) 343 m/s
Fresh water ~1,481 m/s
Seawater ~1,500 m/s
Glass ~3,240 m/s
Steel ~5,960 m/s

Why temperature matters

Warmer air molecules move faster and transmit sound more quickly — roughly 0.6 m/s faster per °C. That’s why the speed of sound (and Mach 1) changes with altitude and weather.

How to use the speed of sound calculator

  1. Choose air (and enter a temperature) or another medium.
  2. Pick °C or °F for air.
  3. Read the speed in m/s, km/h and mph.

Speed of Sound FAQ

How fast does sound travel?

In air at 20 °C, about 343 m/s (767 mph). It's slower in colder air and much faster in water (~1,481 m/s) and steel (~5,960 m/s).

How is the speed of sound in air calculated?

With v = 331.3 × √(1 + T/273.15), where T is in °C. A handy approximation is 331.3 + 0.6 × T.

Why does temperature change it?

Warmer air molecules move faster and pass the sound wave along more quickly — roughly 0.6 m/s faster per degree Celsius.

What is Mach 1?

Mach 1 is the local speed of sound, so it changes with temperature and altitude. At 20 °C it's about 343 m/s.

Why is sound faster in water and metal?

Denser, stiffer materials transmit vibrations more efficiently, so sound travels several times faster than in air.

Is the speed of sound calculator free?

Yes, this speed of sound calculator is completely free, needs no sign-up, and gives instant results in your browser.

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