I recently failed a Gengo standard test. One of the criticisms I received was that metric units should be placed adjacent to the number. After much research online, I found that the majority, if not all, depictions of metric units have a space after the number.

Which method is correct? I was unable to find the specific information regarding it on this site.


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    Interesting question. It seems the style guide doesn't address this specifically, however, I found this example at the end, which indirectly gives a pointer: 

    "Taiko ([[[太鼓]]], literally "big drum") is a Japanese drum measuring 1.3m in diameter, and which is played with wooden sticks called bachi." - https://gengo.com/wp-content/uploads/2014/02/style-guide-en.pdf#page=10

    Searching on the Net, it seems things are not so clear-cut:


    "There is a space between the numerical value and unit symbol, even when the value is used in an adjectival sense, except in the case of superscript units for plane angle." - http://physics.nist.gov/cuu/Units/checklist.html

    "Avoid leaving a space between number and unit of measurement (10km, not 10 km). Commonly used measurements include: cm, mm, km, g, l (litre), MB, GB, kHz, MHz, KB." - http://www.cam.ac.uk/brand-resources/guidelines/editorial-style-guide


    Wikipedia says:

    "The International System of Units (SI) recommends inserting a space between a number and a unit of measurement units and between units in compound units, but never between a prefix and a base unit.

    5.0 cm not 5.0cm or 5.0 c m
    45 kg not 45kg or 45 k g
    32 °C not 32°C or 32° C
    20 kN m not 20 kNm or 20 k Nm
    50 % not 50% (Note: % is not an SI unit, and many style guides do not follow this recommendation)
    The only exception to this rule in the SI the symbolic notation of angles: degree (e.g. 30°), minute of arc (e.g. 22′), and second of arc (e.g. 8″)." - http://en.wikipedia.org/wiki/Space_(punctuation)#Spaces_and_unit_symbols

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    I can confirm both Microsoft's manual of style and the Chicago Manual of Style recommend the same:

    "Insert a space between the number and the unit of measure for all abbreviations."

    The Chicago manual gives examples with spaces in section 9.16.

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    AP style doesn't put  a space. Basically, whatever the style guide says is what goes- which means a decision needs to be made about the style guide *here* (if the client doesn't provide his/her own house style guide)

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    • "9 mm pistol (note the space)"
    • "winds of 5 to 10 mph"

    Unless the site is incorrect, even the AP style guide prefers a space.

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    I appreciate that @wrathoftheseals. My copy is about 100 years old *and* I could be getting mixed up with our own magazine's style guide (quite possible, actually),

    Thanks for taking the time to set me straight.

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