Miles vs Kilometers: Key Differences and How to Convert

A mile (statute mile, abbreviation: mi) is a unit of length equal to exactly 5,280 feet or 1,760 yards. In metric terms, 1 mile = 1.609344 km (exact by international definition). The mile is used as the primary road distance unit in the United States and informally in the UK (UK road signs use miles). In aviation and maritime contexts, the nautical mile (1,852 m) is a separate unit.

Common US references: a 5-mile drive is a short commute; marathon runners cover 26.2 miles; the speed limit on most US interstates is 65–70 miles per hour.

Miles are used on road signs and vehicle speedometers in the United States and, for road signs, in the United Kingdom. Outside of these two countries, kilometers are the universal standard for road distances and speed limits. Canada switched from miles to kilometers in the 1970s; Australia in the 1970s as well. Today, only the US and a handful of other countries still use miles for roads.

For running and athletics: the 5K, 10K, half marathon, and marathon are universally measured in kilometers — but American runners often talk about their per-mile pace. Sports coverage in the US frequently translates metric distances into miles. Meanwhile, Formula 1, cycling's Grand Tours, and most global athletics competitions use kilometers and meters exclusively.