Convert between different speed units including kilometers per hour, miles per hour, meters per second, knots and more with precise calculations and instant results.
The knot originated from sailors measuring speed by dropping a log tied to a rope with knots at regular intervals into the sea. The number of knots that passed through their hands in a specific time period determined the ship's speed.
The Mach number is named after Austrian physicist Ernst Mach and represents the ratio of an object's speed to the speed of sound in the surrounding medium. Mach 1 equals the speed of sound (approximately 343 m/s or 767 mph at sea level).
The speed of light in a vacuum is exactly 299,792,458 meters per second. This is the maximum speed at which all energy, matter, and information can travel through space according to the theory of relativity.
The current land speed record is 763.035 mph (1,227.985 km/h), set by the ThrustSSC team in 1997. This made ThrustSSC the first car to officially break the sound barrier.