km/j or km/jam (Indonesia and Malaysia).Alternative abbreviations in official use SI is also the preferred system of measure in academia and in education. h −1') has now been adopted around the world in many areas related to health and safety and in metrology in addition to the SI unit metres per second ( 'm/s', 'm s −1' or 'm.SI, and hence the use of 'km/h' (or 'km h −1' or 'km This symbol is not merely an abbreviation but a symbol which, like chemical symbols, must be used in a precise and prescribed manner. Hence the name of the unit can be replaced by a kind of algebraic symbol, which is shorter and easier to use in formulae. It has already been stated that, according to Maxwell, when we write down the result of a measurement, the numerical value multiplies the unit. Danloux-Dumesnils provides the following justification for this distinction: The SI explicitly states that unit symbols are not abbreviations and are to be written using a very specific set of rules. The SI standards, which were MKS-based rather than CGS-based were published in 1960 and have since then have been adopted by many authorities around the globe including academic publishers and legal authorities. h −1' being valid representations of 'kilometres per hour'.At the same time the CGPM formalised the rules for combining units – quotients could be written in one of three formats resulting in 'km/h', 'km h −1' and 'km In 1948, as part of its preparatory work for the SI, the CGPM adopted symbols for many units of measure that did not have universally agreed symbols, one of which was the symbol 'h' for 'hours'. Among these were the use of the symbol 'km' for 'kilometre'. In 1879, four years after the signing of the Treaty of the Metre, the International Committee for Weights and Measures (CIPM) proposed a range of symbols for the various metric units then under the auspices of the General Conference on Weights and Measures (CGPM). In military usage, 'klicks' is used, though written as km/h. In informal Australian usage, km/h is more commonly pronounced 'kays' or 'kays an hour'. For example, news organisations such as Reuters and The Economist With no central authority to dictate the rules for abbreviations, various publishing houses have their own rules that dictate whether to use upper-case letters, lower-case letters, periods and so on, reflecting both changes in fashion and the image of the publishing house concerned. 'Kilometres per hour' did not begin to be abbreviated in print until many years later, with several different abbreviations existing near-contemporaneously. The kilometre, a unit of length, first appeared in English in 1810, and the compound unit of speed 'kilometers per hour' was in use in the US by 1866. Abbreviations Ībbreviations for 'kilometres per hour' did not appear in the English language until the late nineteenth century. While these forms remain widely used in non-scientific fields, they are not correct for scientific use with the SI. Several other representations of 'kilometres per hour' have been used since the term was introduced and many are still in use today for example, dictionaries list 'kph', 'km/h', 'kmph' and 'km/hr' as English abbreviations.

The SI representations, classified as symbols, are 'km/h', ' km h −1' and ' km The Dutch on the other hand adopted the kilometre in 1817 but gave it the local name of the mijl ( Dutch mile). In 1802 the term ' myriamètres par heure' appeared in French literature. 2.3 Alternative abbreviations in official useĪlthough the metre was formally defined in 1799, the term 'kilometres per hour' did not come into immediate use – the myriametre ( 10,000 metres) and myriametre per hour were preferred to kilometres and kilometres per hour.Note: For Speed or Velocity conversions, US Customary Units and the Imperial System are equivalent. The following tables provide a summary of the Speed or Velocity units (Per Hour, Per Minute, Per Second and Per Millisecond) within their respective measurement systems.

Convertisseur miles kilometre heure