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Speed of Sound Calculator

Calculate the speed of sound in air at any temperature (or in water and steel), in m/s, ft/s, mph and km/h.

About this tool

Speed of Sound Calculator is a free, in-browser tool that finds how fast sound travels through a medium. For air it uses the temperature you enter (°C or °F); for water and steel it uses standard reference speeds. Results appear in metres per second, feet per second, miles per hour and kilometres per hour. Everything is computed locally — nothing is uploaded.

In air the speed is v = 331.3 · √(1 + T ÷ 273.15) m/s, where T is the temperature in degrees Celsius; the tool also shows the common linear approximation v ≈ 331.3 + 0.606·T so you can see the two agree closely near room temperature. Water is taken as about 1481 m/s and steel about 5960 m/s, both far faster than air because they are much stiffer. The km/h figure is the everyday value of Mach 1 — the speed an object must reach to break the sound barrier at that condition.

Use it to estimate echo and lightning-distance timing, tune acoustics, or check Mach references. Warmer air carries sound faster, which is why the value climbs steadily as you raise the temperature.

Frequently asked questions

How does temperature affect the speed of sound in air?
Sound travels faster in warmer air. The exact relation is v = 331.3 · √(1 + T ÷ 273.15) m/s with T in °C, so at 0 °C sound moves at 331.3 m/s and at 20 °C about 343.2 m/s.
Why are there two air formulas and do they match?
The square-root formula is exact for an ideal gas; the linear form v ≈ 331.3 + 0.606·T is a handy approximation. Near room temperature they agree to within a fraction of a percent, which the tool shows side by side.
What is Mach 1?
Mach 1 is simply the local speed of sound — the km/h tile is that speed in everyday units. An aircraft reaches Mach 1 when its speed equals this value, which changes with temperature and medium.
Is anything uploaded?
No. The calculation happens entirely in your browser; the temperature you type never leaves your device.

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