SI Metric-Matters

Inkorrect Symbols (also seen in print as ‘inKorrect’)

These include:

Kg   Kgs   Km   Kms  


Around the world you have probably seen road signs with the symbol ‘Km’. Perhaps you’ve also seen packets of rice or sacks of potatoes or a market stall with a metric weight label ‘Kg’. Both of these symbols are inkorrect because the capital letter K is used. ‘Kgs’ is also an inkorrect symbol. The symbol ’kg’ does not have a plural form. In fact a leading American Dictionary (Merriam-Webster) accepts the word ‘inkorrect’ exists!

The word ‘inkorrect’
In April 1993 Merriam–Webster Inc. (the major company that produces dictionaries), made the first citation in its files to indicate that the word ‘inkorrect’ exists. The word is to indicate an error, that the correct symbol should not use a capital letter K.

Paul Capellano, the Physical Sciences Editor at Merriam–Webster Inc. wrote a letter to Philip Bladon on 14 April 1993,  he indicated that an actual dictionary entry for ‘inkorrect’ will only be made after the word was in widespread use by its appearance in a variety of publications over a number of years.

So here is a challenge to the reader; if you see any symbols like: ‘Km’ (instead of ‘km’ to represent kilometre), and ‘Kg’ (instead of ‘kg’ to represent kilogram), please ensure that the mistake is brought to the attention of the author and editor of the publication.  Also let other readers know about it.  If details are also sent to Merriam–Webster Inc. then eventually the word should appear as a dictionary entry.

Inkorrect Symbol

Name of unit

Correct Symbol







The prefix ‘kilo’ (symbol ‘k’) must not be used alone it must be used with a unit.

All the correct symbols are shown in a fascinating and unusual book:

A Dictionary Of International Units Metric-Matters: Names and Symbols

Philip Bladon. 2005, Second Edition 2006  
Published: iUniverse.

ISBN: 13: 978-0-595-37115-0  (paperback)
ISBN: 13: 978-0-595-81515-9  (ebook)

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