Kilometre

The kilometre (International spelling as used by the International Bureau of Weights and Measures; SI symbol: km; /ˈkɪləmiːtə/ or /kɪˈlɒmɪtə/) or kilometer (American spelling) is a unit of length in the metric system, equal to one thousand metres (kilo- being the SI prefix for 7003100000000000000♠1000). It is now the measurement unit used officially for expressing distances between geographical places on land in most of the world; notable exceptions are the United States and the road network of the United Kingdom where the statute mile is the official unit used.

k (pronounced /keɪ/) is occasionally used in some English-speaking countries as an alternative for the word kilometre in colloquial writing and speech. A slang term for the kilometre in the US military is klick.

Pronunciation

There are two common pronunciations for the word.

The former follows a pattern in English whereby metric units are pronounced with the stress on the first syllable, and the pronunciation of the actual base unit does not change irrespective of the prefix. It is generally preferred by the British Broadcasting Corporation (BBC) and the Australian Broadcasting Corporation (ABC).

100 kilometres

A length of 100 kilometers (about 62 English miles), as a rough amount, is relatively common in measurements on Earth and for some astronomical objects. It is the altitude at which the FAI defines spaceflight to begin. To help compare orders of magnitude, this page lists lengths between 100 and 1,000 kilometres (10⁵ and 10⁶metres).

Distances shorter than 100 kilometres

Conversions

A distance of 100 kilometres is equal to about 62 miles (or 62.13711922 miles).

Human-defined scales and structures

20 kilometres

The term 20 kilometres may refer to two different races in athletics: