A knot (symbol: kn) is a unit of speed equal to one nautical mile per hour. It is widely used in maritime navigation, aviation, and meteorology because a nautical mile (≈1.852 km) corresponds to one minute of latitude, simplifying chart work.
A kilometer per hour (km/h) is the standard metric unit for speed on land, used in road traffic, automotive engineering, and everyday life.
Why Convert Between kn and km/h?
Mariners planning a coastal route need to compare vessel speed (kn) with weather forecasts that are often given in km/h.
Pilots transitioning between airspeed (kn) and ground speed (km/h) for runway calculations.
Engineers designing hybrid vehicles that operate in both marine and terrestrial environments.
The conversion factor is exact: \(1\ \text{kn}=1.8519984\ \text{km/h}\). This factor comes from the definition of a nautical mile (1,852 meters) divided by 1,000 meters per kilometer.
Knot to Kilometer per hour Conversion Reference Table
Knot (kn)
Kilometer per hour (km/h)
0.1
0.1852
0.5
0.926
1.0
1.852
2.0
3.704
5.0
9.26
10.0
18.52
20.0
37.04
50.0
92.5999
100.0
185.1998
500.0
925.9992
1000.0
1851.9984
Step‑by‑Step Conversion Example
Convert 10 kn to km/h.
Write the known conversion factor: \(1\ \text{kn}=1.8519984\ \text{km/h}\).
Multiply the speed in knots by the factor.
\[\displaystyle 10\ \text{kn}\times1.8519984\ \frac{\text{km}}{\text{h}}\]
Calculate the product.
\[\displaystyle 10\times1.8519984=18.519984\ \text{km/h}\]
Round as appropriate (usually to two decimal places): \(\approx18.52\ \text{km/h}\).
The factor 1.8519984 is derived from the exact definition of a nautical mile (1,852 m). It is precise to seven decimal places, more than sufficient for engineering and navigation calculations. Rounding to 1.852 is common for quick estimates.
Use knots when dealing with any system that references nautical distances—marine vessels, aircraft, or oceanographic instruments. For land‑based transport, road vehicles, and most consumer products, km/h remains the standard.
"On fait la science avec des faits, comme on fait une maison avec des pierres ; mais une accumulation de faits n'est pas plus une science qu'un tas de pierres n'est une maison." "Science is built up of facts, as a house is built of stones; but an accumulation of facts is no more a science than a heap of stones is a house." — Henri Poincaré (French Mathematician, Theoretical Physicist & Mining Engineer)