Speed of Sound Calculator
From a single air temperature, get how fast sound travels through dry air — the number behind echo timing, thunder distances, and acoustics.
One temperature, one speed
Enter the air temperature in °C and the calculator returns the speed of sound in metres per second using v = 331.3 + 0.606 × T.
Dry-air approximation
This is the common linear formula for dry air. Humidity and altitude nudge the value slightly, so treat it as a close everyday estimate.
What is a speed of sound calculator?
Temperature in, sound speed out
A speed of sound calculator turns one measurement — the air temperature — into how fast a sound wave travels through that air. The speed is not fixed: it climbs as the air warms, because faster-moving molecules pass the disturbance along more quickly. In dry air the relationship is almost perfectly linear, so a single formula covers everything from a frosty winter morning to a hot summer afternoon. That makes the temperature the only input you need for echo timing, thunder-distance estimates, music and acoustics, and physics homework where sound speed shows up.
Enter the air temperature in °C to get the speed of sound in dry air instantly, in metres per second.
One short formula, built from the air temperature and two fixed constants.
v = 331.3 + 0.606 × TThe constant 331.3 is the speed of sound in dry air at 0 °C, in m/s. The coefficient 0.606 is how many extra m/s you gain for each degree Celsius the air warms. Multiply 0.606 by the temperature T (in °C), add 331.3, and you have the speed v in m/s. Because the formula is linear, the speed rises in a straight line: every degree warmer adds the same small amount.
Suppose the air temperature is 20 °C.
Scale the temperature
0.606 × 20 = 12.12 — the speed gained from the warmth above 0 °C.
Add the 0 °C baseline
331.3 + 12.12 = 343.42 — add the dry-air speed at the freezing point.
Read the result
Sound travels about 343.42 m/s through dry air at 20 °C.
The number tells you how far a sound travels each second through the air around you. At 20 °C that is about 343.42 m/s, so a thunderclap heard three seconds after the lightning flash came from roughly one kilometre away — a handy field estimate. The key insight is that the speed depends on temperature, not on how loud the sound is or how far it has gone. Warmer air carries sound faster: each degree Celsius adds about 0.6 m/s, so on a 30 °C day sound moves noticeably quicker than at the 0 °C freezing point, where it drops to about 331 m/s. That temperature link matters for musicians tuning to a room, for sound engineers placing speakers, and for anyone timing echoes or sonar pulses. Remember that this is a dry-air formula: humidity and altitude shift the real value a little, usually by well under one percent, so use it as a close everyday approximation rather than an exact laboratory figure.
The formula is simple and reliable, but a couple of practical points are worth keeping in mind.
Dry air and a sensible temperature range
This is the linear dry-air approximation. Real air carries some moisture, which lets sound travel marginally faster, and very high or very low temperatures drift slightly from the straight-line fit used here. The formula also only makes physical sense above absolute zero (−273.15 °C), since air cannot exist as a gas below that, so the calculator returns no result for temperatures at or below it.