Knot (Speed)

A unit of speed equal to one nautical mile per hour.

One knot is exactly 1.852 kilometres per hour and approximately 1.151 statute miles per hour. Because a knot already means nautical miles per hour, expressions such as ‘knots per hour’ are incorrect when stating speed.

The unit is used for vessel speed, current and wind. Speed through the water, speed over the ground and wind speed describe different measurements even when all are expressed in knots; the intended reference should therefore be stated.