Flexi Says: One kilometer (km) is equal to 0.621371 miles (mi). One km is also equal to 1000 meters (m), the standard SI unit for length. Originally, the meter was defined as the length between two scratches on a piece of metal which was stored in a secure vault under controlled conditions. The meter's definition has changed over time, but it is now accepted to be the distance light travels in a vacuum over 1/299792458 of a second.
