Get Kilometre essential facts below. View Videos or join the Kilometre discussion. Add Kilometre to your topic list for future reference or share this resource on social media.

Unit systemmetric
Unit oflength
SI units
imperial/US units

nautical units0.53996 nmi

The kilometre (SI symbol: km; or ), spelt kilometer in American English, is a unit of length in the metric system, equal to one thousand metres (kilo- being the SI prefix for ). 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.

The abbreviations k or K (pronounced ) 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]


There are two common pronunciations for the word.[5]

The first pronunciation follows a pattern in English whereby metric units are pronounced with the stress on the first syllable (as in kilogram, kilojoule and kilohertz) and the pronunciation of the actual base unit does not change irrespective of the prefix (as in centimetre, millimetre, nanometre and so on). It is generally preferred by the British Broadcasting Corporation (BBC), the Canadian Broadcasting Corporation (CBC), and the Australian Broadcasting Corporation (ABC).[]

Many scientists and other users, particularly in countries where the metric system is not widely used, use the second pronunciation with stress on the second syllable.[6][7] The second pronunciation follows the stress pattern used for the names of measuring instruments (such as micrometer, barometer, thermometer, tachometer and speedometer). The contrast is even more obvious in countries using the Commonwealth spelling rather than American spelling of the word metre.

When Australia introduced the metric system in 1975, the first pronunciation was declared official by the government's Metric Conversion Board. However, the Australian prime minister at the time, Gough Whitlam, insisted that the second pronunciation was the correct one because of the Greek origins of the two parts of the word.[8]

Equivalence to other units of length


Historical divisions of the meridian in France

By a decree of 8 May 1790, the French National Constituent Assembly ordered the French Academy of Sciences to develop a new measurement system. In August 1793, the French National Convention decreed the metre as the sole length measurement system in the French Republic and it was based on 1/10 millionth of the distance from the orbital poles (either North or South) to the Equator, this being a truly internationally based unit. The first name of the kilometre was "Millaire". Although the metre was formally defined in 1799, the myriametre ( metres) was preferred to the "kilometre" for everyday use. The term "myriamètre" appeared a number of times in the text of Develey's book Physique d'Emile: ou, Principes de la science de la nature,[11] (published in 1802), while the term kilometre only appeared in an appendix. French maps published in 1835 had scales showing myriametres and "lieues de Poste" (Postal leagues of about  metres).[12]

The Dutch, on the other hand, adopted the kilometre in 1817 but gave it the local name of the mijl.[13] It was only in 1867 that the term "kilometer" became the only official unit of measure in the Netherlands to represent  metres.[14]

Two German textbooks dated 1842[15][16] and 1848[17] respectively give a snapshot of the use of the kilometre across Europe: the kilometre was in use in the Netherlands and in Italy, and the myriametre was in use in France.

In 1935, the International Committee for Weights and Measures (CIPM) officially abolished the prefix "myria-" and with it the "myriametre", leaving the kilometre as the recognised unit of length for measurements of that magnitude.[18]

Kilometre records

Some sporting disciplines feature (one-kilometre) races in major events (such as the Olympic Games). In some disciplines--although world records are catalogued--one-kilometre events remain a minority.

1 km world records for various sporting disciplines
Discipline Name Time (min:sec) Location Date Comments
Running (M) Noah Ngeny 2:11.96[19] Rieti, Italy 5 Sep 1999 Not an Olympic event
Running (F) Svetlana Masterkova 2:28.98[20] Brussels 23 Aug 1996 Not an Olympic event
Speed skating (M) Pavel Kulizhnikov 1:05.69 Salt Lake City 15 Feb 2020
Speed skating (F) Cindy Klassen 1:13.11[21] Calgary 25 Mar 2006
Track cycling (M) François Pervis 56.303[22] Aguascalientes, Mexico 7 Dec 2013 No official women's record

See also


  1. ^ "Kilometre". Oxford Learner's Dictionaries. Retrieved 2019.
  2. ^ "The International System of Units (SI)" (PDF). International Bureau of Weights and Measures (BIPM). 2019. pp. 147-149. Retrieved 2020.
  3. ^ "MARINE CORPS JARGON" (PDF). Retrieved 2017.
  4. ^ Rod Powers. "How Far is a 'Klick' in the Military?". Archived from the original on 17 February 2006. Retrieved 2010.
  5. ^ Jones, Daniel (2003) [1917], Peter Roach; James Hartmann; Jane Setter (eds.), English Pronouncing Dictionary, Cambridge: Cambridge University Press, ISBN 3-12-539683-2
  6. ^ White, Roland (23 March 2008). "Correct pronunciation on the radio". The Times. London. Retrieved 2010.
  7. ^ "Kilometer - Definition and More from the Free Merriam-Webster Dictionary". Retrieved 2014.
  8. ^ "damage lessons". Retrieved 2014.
  9. ^ One astronomical unit is currently accepted to be equal to .
  10. ^ A light-year is equal to the distance light travels through vacuum in one year (365.25 days).
  11. ^ Develey, Emmanuel (1802). Physique d'Emile: ou, Principes de la science de la nature. Vol. 1. Paris.
  12. ^ Map of the department of Hautes Pyrénées (Map). France Pittoresque (in French). Laguillermie et Rambos. 1835. Retrieved 2012.
  13. ^ Jacob de Gelder (1824). Allereerste Gronden der Cijferkunst [Introduction to Numeracy] (in Dutch). 's-Gravenhage and Amsterdam: de Gebroeders van Cleef. pp. 155-156. Retrieved 2011.
  14. ^ "[News from] Nederland" (PDF). De Locomotief. Nieuws, handels en Advertentie-blad. 12 August 1869. p. 2. Archived from the original (PDF) on 27 February 2017.
  15. ^ "Amtliche Maßeinheiten in Europa 1842" [Official units of measure in Europe 1842] (in German). Retrieved 2011Text version of Malaisé's book{{cite web}}: CS1 maint: postscript (link)
  16. ^ Ferdinand Malaisé (1842). Theoretisch-practischer Unterricht im Rechnen [Theoretical and practical instruction in arithmetic] (in German). München. pp. 307-322. Retrieved 2011.
  17. ^ Mozhnik, Franz (1848). Lehrbuch des gesammten Rechnens für die vierte Classe der Hauptschulen in den k.k. Staaten [Arithmetic textbook for the fourth class in the [Austrian] Imperial and [Hungarian] Royal states] (in German). Vienna: Im Verlage der k.k. Schulbücher Verschleiß-Administration. Das Wegmaß. Retrieved 2013.
  18. ^ McGreevy, Thomas (1997). Cunningham, Peter (ed.). The Basis of Measurement - Volume 2 - Metrication and Current Practice. Picton. ISBN 0-948251-84-0.
  19. ^ "Men's World Records". Track and Field. Retrieved 2011.
  20. ^ "Women's World Records". Track and Field. Retrieved 2011.
  21. ^ "Speed Skating: Complete history list of World Records recognized by ISU" (PDF). International Skating Union. 7 March 2009. Archived from the original (PDF) on 5 February 2012. Retrieved 2011.
  22. ^ "Pervis sets new kilometre world record in Mexico". Cycling News. Retrieved 2021.

External links

Listen to this article (12 minutes)
Spoken resource icon
This audio file was created from a revision of this article dated 27 June 2013 (2013-06-27), and does not reflect subsequent edits.

  This article uses material from the Wikipedia page available here. It is released under the Creative Commons Attribution-Share-Alike License 3.0.



Music Scenes