Speed of Sound Calculator: knots, mach, mph

Calculate the speed of sound in various units (Knots, Mach, MPH, km/h, m/s, ft/s) based on the air temperature. Enter your air temperature and select the temperature unit to find the speed of sound.

In the Earth’s atmosphere, the chief factor affecting the speed of sound is the temperature.

>> Temperature Converter: Convert to/from °F, °C, K

The speed of sound refers to how fast sound waves travel through a medium such as air, water, or a solid. In the Earth’s atmosphere, the speed of sound is influenced by factors such as:

• Temperature (the main factor)
• Humidity
• Altitude/Pressure

The speed of sound in the atmosphere is calculated using the following formula:

V_sound = 643.855 x (T / 273.15)^0.5

Where:

• v_sound is the speed of sound in knots.
• T is the air temperature in Kelvin.
• 643.855 is a constant used to calculate the speed of sound in knots.

Note: Mach 1 is defined as the speed of sound under standard atmospheric conditions, which are 288.15 Kelvin (15°C or 59°F). Under these conditions, the speed of sound is approximately 343 meters per second (m/s).