The kilometre (SI symbol: km; /ˈkɪləmtər/ or /kɪˈlɒmɪtər/), spelled kilometer in American English, is a unit of length in the metric system, equal to one thousand metres (kilo- being the SI prefix for 1000). It is now the measurement unit used for expressing distances between geographical places on land in most of the world; notable exceptions are the United States and the United Kingdom where the statute mile is the unit used.

Unit systemmetric
Unit oflength
1 km in ...... is equal to ...
   SI units   1000 m
   imperial/US units   0.62137 mi
1093.6 yd
3280.8 ft
   nautical units   0.53996 nmi

The abbreviations k or K (pronounced /k/) are commonly used to represent kilometre, but are not recommended by the BIPM.[1][2] A slang term for the kilometre in the US, UK, and Canadian militaries is klick.[3][4]