Convert miles to km
Please provide values below to convert mile [mi] to kilometer [km], or vice versa.
Mile
Definition: A mile (symbol: mi) is a unit of length in the imperial and US customary systems of measurement. The international mile is precisely defined as 5,280 feet, 1,760 yards, or exactly 1.609344 kilometers.
History/origin: The term "mile" is derived from the Latin "mille passus," meaning "thousand paces," which measured the distance of 1,000 paces of a Roman legion. A Roman pace was the distance of a double step, roughly five Roman feet, making the Roman mile about 1,480 meters or 4,856 feet. The current international mile was standardized in 1959 by an agreement among the United States, United Kingdom, Canada, Australia, New Zealand, and South Africa, defining it exactly in terms of the meter as 1.609344 kilometers.
Throughout history, there have been many variations of the mile, including the statute mile, the nautical mile (still used in maritime and aviation contexts), and the survey mile (used in the U.S. Public Land Survey System). The statute mile of 5,280 feet became established in English law by a statute in 1593 during the reign of Queen Elizabeth I, when it superseded the old English mile of 5,000 feet.
Current use: The mile is primarily used in the United States and the United Kingdom for road distances, although the UK has largely switched to kilometers for other purposes. In the United States, it remains the standard unit for measuring longer distances on roads, for races like the "mile run," and in everyday conversation. The nautical mile (approximately 1.15078 statute miles) is still used worldwide for maritime navigation and aviation. Miles per hour (mph) is the standard unit of speed on roads in the United States and United Kingdom.
Kilometer
Definition: A kilometer (symbol: km) is a unit of length in the International System of Units (SI), equal to 1,000 meters (0.621371 miles).
History/origin: The kilometer is part of the metric system, which originated in France during the French Revolution in the late 18th century. The prefix "kilo" comes from the Greek word "χίλιοι" (chilioi), meaning "thousand." The metric system was designed to be logical and universal, with each unit related to others by powers of ten, making conversions simple. The meter was originally defined as one ten-millionth of the distance from the North Pole to the equator along a meridian running through Paris, and a kilometer is simply 1,000 of these units.
In 1875, the Treaty of the Meter was signed, establishing the International Bureau of Weights and Measures (BIPM) to maintain international standards for the meter and other units. Over time, the definition of the meter has been refined for greater precision, but the kilometer has consistently remained 1,000 meters. The modern definition of the meter is based on the speed of light in vacuum, which has made the kilometer an extremely precise unit of measurement.
Current use: The kilometer is the primary unit used for expressing distances between geographical places on land in most of the world. Road signs in most countries express distances in kilometers, and maps typically use this unit for measuring distances. It is also commonly used in scientific contexts worldwide. In countries that use the metric system (which is most of the world), the kilometer is the standard unit for medium to long distances. Speed limits and odometers in vehicles are also typically measured in kilometers per hour (km/h) outside the United States and a few other countries.