Convert km to miles

キロ

定義
A kilometer (symbol: km) is an SI unit of length equal to 1 000 meters. In everyday terms, one kilometer equals approximately 0.6214 statute miles.

起源
接頭辞キロ (ギリシャ語 chilioi, “thousand”) indicates a factor of 10³. As the metric system evolved, the kilometer naturally emerged as the 1 000× multiple of the meter, which today is defined by the distance light travels in 1/299 792 458 of a second. Although the meter’s definition has changed over time, the relationship (1 km = 1 000 m) remains fixed.

現代の使用
Kilometers are the standard for expressing land distances in most countries worldwide—on road signs, maps, and in athletic events. Exceptions include the U.S. and Liberia, which commonly use miles, and the U.K., where road distances remain in miles despite metric adoption in other contexts.

マイル

定義
A (statute) mile (symbol: mi) is an Imperial and U.S. customary unit of length defined as exactly 1 609.344 meters, or 5 280 feet.

起源
ラテン語に由来する ミルパサス (“thousand paces”), the mile has roots in Roman surveying. In 1593 England formalized the statute mile at 8 furlongs (5 280 ft). Variants like the nautical mile (1 852 m) and historical “Roman mile” (5 000 ft) persist in specialized uses.

現代の使用
Miles remain standard on highways in the U.S., U.K., and some Commonwealth countries. They also appear in aviation and maritime contexts alongside nautical miles.