✈️ Mach Number Calculator
Find the Mach number of an object by comparing its speed to the local speed of sound, which depends on air temperature.
What Mach number means
The Mach number is the ratio of an object’s speed to the local speed of sound in the surrounding air. Mach 1 means traveling exactly at the speed of sound; Mach 2 means twice the speed of sound, and so on.
The formula
This calculator first finds the local speed of sound using a = √(γ × R × T), where γ is the ratio of specific heats for air (1.4), R is the specific gas constant for dry air (287.05 J/(kg·K)), and T is the absolute air temperature in kelvin. The Mach number is then your object’s speed divided by that speed of sound. Because sound travels faster in warmer air, the same physical speed produces a slightly different Mach number depending on temperature.
This tool uses standard dry-air approximations and is intended for general educational and planning use, not for certified aerospace engineering calculations.