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Speed of sound calculator

How fast sound travels — through air at a given temperature (c ≈ 331.3·√(1+T/273.15) m/s, a touch faster in humid air), or through another medium from a reference table (water ~1481 m/s, steel ~5960 m/s). Results in m/s, km/h and mph, with the Mach-1 reference.

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Need Speed (m/s), Speed (km/h), Speed (mph)? The Speed of sound calculator derives it from Medium, Air temperature (°C), Relative humidity (%, air) in one step. For instance, with Medium = Air (by temperature), Air temperature (°C) = 20 and Relative humidity (%, air) = 0 it returns Speed (m/s) = 343.215, Speed (km/h) = 1,236 and Speed (mph) = 767.749.

How to use it

  1. Enter your values: Medium, Air temperature (°C), Relative humidity (%, air).
  2. Read the result instantly: Speed (m/s), Speed (km/h), Speed (mph).

Frequently asked questions

How does the Speed of sound calculator work?

It takes Medium, Air temperature (°C) and Relative humidity (%, air) and derives Speed (m/s), Speed (km/h) and Speed (mph) from them. The calculation is live as you type, so the result updates on every change.

Which values does the calculator ask for?

3 values: Medium, Air temperature (°C) and Relative humidity (%, air). Nothing else is required — no account, no file upload.

What does a typical calculation look like?

With Medium = Air (by temperature), Air temperature (°C) = 20 and Relative humidity (%, air) = 0, the calculator returns Speed (m/s) = 343.215, Speed (km/h) = 1,236 and Speed (mph) = 767.749. Those figures come from running this exact tool, so you can reproduce them by entering the same values.

How much does the result change with different inputs?

It moves a lot. Using Medium = Fresh water, Air temperature (°C) = 40 and Relative humidity (%, air) = 5 instead, Speed (m/s) goes from 343.215 to 1,481 — which is why it is worth testing a few scenarios rather than trusting a single figure.

Which “Medium” option should I choose?

You can pick between « Air (by temperature) », « Fresh water », « Sea water », « Steel », « Aluminium » and « Glass ». Each one changes what the calculator works out, so switch and compare — the default is « Air (by temperature) ».

What does it give for smaller values?

Scaled down to Medium = Air (by temperature), Air temperature (°C) = 10 and Relative humidity (%, air) = 1, Speed (m/s) comes out at 337.312. The relationship is worth checking at both ends before you rely on a single result.

When would I actually use this?

Checking a homework answer, sizing something before building it, and getting an order of magnitude before committing to a design — a torque on a bolt, the force a spring returns, the frequency a circuit resonates at, how long light takes to arrive.

What is the most common mistake?

Feeding in a value in the wrong unit. Physics formulas assume SI throughout, so grams instead of kilograms or centimetres instead of metres shifts the answer by powers of ten without any warning.

What is the difference between the Speed of sound calculator and the Wave speed calculator?

This one returns Speed (m/s) and Speed (km/h); the Wave speed calculator returns Wave speed (m/s). That is the whole difference — open the one whose figure you need.

Is there a tool for the next step?

Kinetic energy chicken cooker is the closest one after this: A famous physics joke, made calculable: could you cook a chicken by throwing it? Each throw deposits kinetic energy ½mv²; cooking it needs enough heat to raise it to 74 °C (Q = m·c·ΔT). It reports the energy per throw and how many throws — at your chosen speed — the meal would take.

Further reading

All guides →
ExplainerHow the Doppler Effect Works: The Formula, the Sign Convention, and Why Moving the Source Is Not the Same as Moving the ListenerFor sound, f' = f(v + v_o)/(v − v_s) — and getting the signs backwards is the classic error. Here is the convention spelled out, a 440 Hz source computed at four speeds, and why light needs a different equation entirely.ExplainerWhat Is the Reynolds Number? The Formula, the Units That Cancel, and Why 2 300 Is Only for PipesRe = ρvL/μ compares inertia with viscosity, and the units really do cancel. See the number worked out for honey, a household pipe, an artery, a swimmer and a wing — and why the 2 300 threshold belongs to pipe flow alone.ExplainerHow Buoyancy Works: Archimedes' Principle, and Why Ice Floats With 10.5 % Above WaterThe upward force equals the weight of the fluid pushed aside. That one sentence decides whether something floats, and if it floats, exactly how much of it stays under.ExplainerHooke's Law Explained: F = kx, Real Spring Constants, and Where It Stops HoldingHooke's law says force is proportional to stretch — but only below the elastic limit. Here is F = kx with worked numbers, what a 200 N/m spring actually feels like, and how springs combine.GuideThe Four Kinematics Equations: Which One to Use, and What Each One Leaves OutFive variables, four equations, and each equation is missing exactly one of them. Choose by looking at the variable the question never mentions.ExplainerProjectile Motion Explained: Range, Height, Flight Time — and Why 45° Is Not Always BestThree formulas cover the whole of projectile motion on level ground. The catch is level ground: the moment launch and landing heights differ, the 45° result stops being true.