Convert 21 kilometers per hour to knots

Precise decimal and fraction answers

The conversion in knots rounded to six significant decimal places is 21 km/h = 11.339093 kn. The precise fraction answer is 11 ¹⁵⁷/₄₆₃ kn.

How many knots is a kilometer per hour?

A kilometer per hour is slower than a knot. 0.54 knots is the same velocity as one kilometer per hour. A kilometer per hour is 54.00% the velocity a knot. An object moving at a knot is 85.2% faster than an object traveling at one kilometer per hour.

Kilometers per hour to knots conversion factor and formulas

The conversion factor between kilometers per hour and knots is 1.852. This represents the ratio of kilometers per hour per one knot. To calculate the value in knots, we can either divide by the conversion factor or multiply by its inverse.

Division

To convert from kilometers per hour to knots, divide kilometers per hour by 1.852.
The formula is expressed as:
km/h ÷ 1.852 = kn

Multiplication

Alternatively we can multiply by the inverse conversion factor to get the same result.
The inverse of 1.852 is 1/1.852 or 0.54. To convert from kilometers per hour to knots, multiply kilometers per hour by 0.54.
The formula is expressed as:
km/h × 0.54 = kn

To convert 21 kilometers per hour to knots, divide 21 kilometers per hour by 1.852.
21 km/h ÷ 1.852 = 11.339 kn

How fast are 21 kilometers per hour?

Real world scale examples to visualize the velocity of 21 kilometers per hour / 11.339 knots

• 1.09 times the comfortable bicycling speed (12 mph)
• 35% of the typical speed of a racehorse (37 mph)
• 19% of the typical automobile speed on a highway (70 mph)

About this conversion

Converting kilometers per hour to knots is a conversion between units from separate unit systems - kilometers per hour are metric (SI) defined units while knots are US Customary / UK Imperial .

About Kilometers per hour

Within the SI (metric) system of measurement, a kilometer per hour (km/h) is the distance traveled in one hour as measured in kilometers (1,000 meters). It is commonly used as measurement of velocity over geographic distances. Kilometers per hour are commonly used to measure vehicle speed and speed limits. The official SI symbol is km/h, however kph and km/hr are also used.

About Knots

Knots are a measure of speed over long geographic distances most often associated with the maritime and aviation communities. A knot is a measurement of distance traveled in nautical miles in one hour. The origins of the knot derive from practice of mariners throwing a wooden chip log attached to a line off the stern of a ship. As the ship traveled forward, the line spooled out and the number of physical knots on the line where counted over a 30 second period to determine boat speed. The symbol for knots is either kn or kt.

Reverse this conversion

Convert from knots to kilometers per hour instead.

References and Citations

1. International Bureau of Weights and Measures (BIPM) The International System of Units (SI)
2. National Institute of Standards and Technology (NIST) General Tables of Units of Measurement