Calculation
c = 331.3 + 0.606·T
Speed of sound in air increases approximately linearly with temperature, since warmer air has a higher mean molecular speed.
Lineare Näherung c ≈ 331,3 + 0,606·T (°C) der idealen Gasbeziehung wS = √(κ·R·T) nach Dubbel Thermodynamik D 7.2.1
Speed of sound in air from temperature
Speed of sound in air increases approximately linearly with temperature, since warmer air has a higher mean molecular speed.
MINTSI
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Result
Select a target and calculate.
Understand the inputs
- Speed of sound c — Propagation speed of sound in still, dry air at the given temperature.
- Air temperature T — Temperature of the air the sound propagates through.
Example
T=20 °C gives c=331.3+0.606·20≈343.4 m/s.
Assumptions and limits
Dry, still air at standard pressure; humidity, wind speed and temperature ranges far from 0 °C outside the linear approximation's valid range are excluded.
Understand Speed of sound in air from temperature
This calculator determines the speed of sound in dry air from air temperature, the basis for travel-time measurements such as echo sounding or ultrasonic sensing.
What does this quantity describe?
For dry air at standard pressure, the linear approximation c=331.3+0.606·T (T in °C) holds, derived from the more exact relation via the ideal gas law.
Formula and variables
c = 331.3 + 0.606·T
c = 331.3 + 0.606·TT = (c−331.3)/0.606
| Symbol / input | Meaning |
|---|---|
| Speed of sound c | Propagation speed of sound in still, dry air at the given temperature. |
| Air temperature T | Temperature of the air the sound propagates through. |
Choose the inputs correctly
T is the air temperature through which the sound propagates.
How to use the calculator
Measure T at the location of sound propagation; use a representative average for larger temperature variation along the path.
Worked example
T=20 °C gives c=331.3+0.606·20≈343.4 m/s.
Understand the result and units
Speed of sound rises with temperature; at a wintry −10 °C it falls to about 325 m/s, at a summery 30 °C it rises to about 349 m/s.
T is a temperature. c is output as a speed.
Typical applications
Basis for travel-time measurements (echo sounding, ultrasonic sensors, lightning-thunder distance estimation) and acoustic calculations generally.
Assumptions, limits and common mistakes
Dry, still air at standard pressure; humidity (slightly raises c), wind speed, and temperatures far from 0 °C outside the linear approximation's valid range are excluded.
Common mistake: Do not confuse the speed of sound in vacuum or water with that in air; the values differ by more than a factor of four.
Frequently asked questions
What is “Speed of sound in air from temperature” used for?
Basis for travel-time measurements (echo sounding, ultrasonic sensors, lightning-thunder distance estimation) and acoustic calculations generally.
Where do the input values come from?
T is the air temperature through which the sound propagates.
What does the result not cover?
Dry, still air at standard pressure; humidity (slightly raises c), wind speed, and temperatures far from 0 °C outside the linear approximation's valid range are excluded.