What is knot?

A knot is a unit of speed equal to one nautical mile per hour, approximately 1.852 km/h. It is the international standard for maritime navigation, aviation, and meteorological wind speed reporting.

Real-world uses

Knots are the universal speed unit in maritime navigation and aviation worldwide, regardless of whether a country uses metric or imperial. Ship speeds, ocean currents, wind speed in aviation weather (METAR) reports, and jet stream velocities are all given in knots.

History

The knot originates from the 17th-century practice of measuring ship speed by throwing a log overboard attached to a rope with knots tied at regular intervals. Sailors counted how many knots paid out in a fixed time (measured by a sandglass).

Common mistakes

Saying "knots per hour"—a knot already means nautical miles per hour, so adding "per hour" is redundant and incorrect. Also, confusing knots with km/h: 1 knot ≈ 1.852 km/h.

What is kilometre per hour?

Kilometre per hour is a unit of speed equal to one kilometre travelled in one hour. It is the most widely used unit for road speed limits, vehicle speedometers, and wind speeds in metric countries.

Real-world uses

Kilometres per hour is the standard speed unit for road traffic in most countries, displayed on car speedometers, speed limit signs, and GPS devices. Weather services report wind speeds in km/h, and athletes track running pace in min/km.

History

Kilometres per hour became widespread as the metric system was adopted for road transport in the 20th century. The first metric speed limits appeared in continental Europe. Today, km/h is used in about 91% of the world's countries for traffic regulation.

Common mistakes

Confusing km/h with m/s—100 km/h is about 27.78 m/s, not 100 m/s. Also, when converting to mph, people often use a rough factor of 1.5 instead of the correct 1.609, leading to inaccurate speed comparisons.

When is this conversion used?

Converting between knot and kilometre per hour is common when working across metric and imperial systems, such as international trade, travel between countries with different measurement standards, or following instructions from a different region. Speed limits, vehicle speedometers, and weather reports for wind speeds use different units depending on the country, making km/h to mph conversion one of the most practical speed conversions.

Worked examples

1 knot = 1.852 kilometre per hour

1 kilometre per hour = 0.27777778 metre per second

How to convert knot to kilometre per hour

To convert knot to kilometre per hour, multiply the value by 1.852.

To convert kilometre per hour back to knot, multiply by 0.5399568.

Measurement standards

The SI unit of speed is metres per second (m/s), a derived unit requiring no independent definition. The knot is defined as exactly one nautical mile (1,852 metres) per hour and is sanctioned for maritime and aeronautical navigation by the International Civil Aviation Organization.

Did you know?

The fastest human-made object is the Parker Solar Probe, which reached 635,266 km/h (about 176 km/s) in 2024 during a close pass of the Sun — fast enough to travel from New York to Tokyo in under a minute.

Quick reference: knot to kilometre per hour

knot	kilometre per hour
0.1	0.1852
0.5	0.926
1	1.852
2	3.704
5	9.26
10	18.52
25	46.29999999
50	92.59999998
100	185.19999997
250	462.99999992
500	925.99999985
1,000	1,851.99999969

Common values

	knot	kilometre per hour
Walking speed	2.72138229 knot	5.04 kilometre per hour
City speed limit	27.01943845 knot	50.04 kilometre per hour
Highway driving	60.84233262 knot	112.67999999 kilometre per hour
Commercial aircraft	485.96112315 knot	899.99999993 kilometre per hour
Speed of sound (sea level)	661.47084239 knot	1,225.0439999 kilometre per hour

Available Speed units

More knot conversions

Assumption: Mach uses an approximate sea-level reference (about 340.29 m/s).