Speed of Sound Calculator
Calculate the speed of sound in air as a function of temperature using v = 331.3 + 0.606T (°C). Understand how temperature affects acoustic wave propagation for audio and atmospheric science.
This free online speed of sound calculator provides instant results with no signup required. All calculations run directly in your browser — your data is never sent to a server. Enter your values below and see results update in real time as you type. Perfect for everyday calculations, homework, or professional use.
Results
Speed of Sound
343.4 m/s
How to Use This Calculator
Enter your input values
Fill in all required input fields for the Speed of Sound Calculator. Most fields include unit selectors so you can work in your preferred unit system — metric or imperial, whichever matches your problem.
Review your inputs
Double-check that all values are correct and that you have selected the right units for each field. Incorrect units are the most common source of calculation errors and can produce results that are off by factors of 2, 10, or more.
Read the results
The Speed of Sound Calculator instantly computes the output and displays results with units clearly labeled. All calculations happen in your browser — no loading time and no data sent to a server.
Explore parameter sensitivity
Try adjusting individual input values to see how the output changes. This is a quick and effective way to develop intuition about how different parameters influence the result and to identify which inputs have the largest effect.
When to Use This Calculator
- •Use the Speed of Sound Calculator when you need accurate results quickly without the risk of manual computation errors or unit conversion mistakes.
- •Use it to verify calculations made by hand or in spreadsheets — an independent check can catch errors before they lead to costly decisions.
- •Use it to explore how changing input parameters affects the output — a quick way to develop intuition and identify the most influential variables.
- •Use it when collaborating with others to ensure everyone is working from the same numbers and applying the same assumptions.
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About Speed of Sound Calculator
The Speed of Sound Calculator determines how fast sound travels through air at a given temperature. Sound speed increases with temperature because hotter air molecules move faster and transmit pressure waves more efficiently. At 20°C, sound travels at about 343 m/s (1235 km/h or 767 mph). This is critical for acoustics, audio engineering, sonar, aviation (Mach number), and understanding phenomena like thunder delay, echoes, and sonic booms. The 3-second rule for estimating lightning distance relies on this speed.
The Math Behind It
Formula Reference
Speed of Sound in Air
v = 331.3 + 0.606T
Variables: T = temperature in °C (valid near room temperature)
Worked Examples
Example 1: Room Temperature
T = 20°C
Speed of sound: 343.4 m/s (1236 km/h).
Example 2: Cold Day
T = −10°C
Speed of sound: 325.2 m/s — noticeably slower in cold air.
Common Mistakes & Tips
- !Using this formula for media other than air — each medium has its own speed of sound.
- !Confusing temperature in Celsius with Kelvin in the simplified formula (this formula uses °C).
- !Assuming sound speed is constant — it varies significantly with temperature, humidity, and altitude.
Related Concepts
Used in These Calculators
Calculators that build on or apply the concepts from this page:
Frequently Asked Questions
Why does thunder come after lightning?
Lightning and thunder occur simultaneously, but light travels at 300,000 km/s while sound travels at only 343 m/s. Sound takes about 3 seconds per kilometer. Count seconds between flash and thunder, divide by 3 for distance in km.
Why does helium make your voice squeaky?
Sound travels 2.9× faster in helium than in air. Your vocal cords vibrate at the same frequency, but the resonant frequencies of your vocal tract shift upward because they depend on the speed of sound in the gas filling it.
Is there sound in space?
No. Sound requires a medium (gas, liquid, or solid) to propagate. Space is nearly a vacuum. However, certain extremely low-density plasma clouds in space can transmit very low-frequency pressure waves.
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