What this calculator does
Mach number works out speed of an object relative to the local speed of sound in air. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaM = v/c; c = 331.3√(1 + T/273.15) m/s for air at temperature T
The inputs explained
| Field | What to enter |
|---|---|
| Object speed (m/s) | A number, measured in m/s. Starts at 300. |
| Air temperature (°C) | A number, measured in °C. Starts at 20. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with object speed
Every other input is held at the calculator’s starting values while object speed varies. Select any row to load that scenario into the calculator.