It seems that pretty much all documentation I've read is clear on where to place the currency symbol when dealing with currency amounts in English (let us assume English from UK for this example):

  • £100
  • €100
  • GBP 100
  • EUR 100

So, basically, the currency symbol comes before the number and the space is only used when using ISO codes.

However, for all other units I assume the convention is the international standard (units on the right and separated with a space):

  • 100 m (meters)
  • 50 s (seconds)

So, what is the rule to follow when units are currency per meter (imagine the price of a metal rod) or currency per time (price of an international phone call)?

  • 100 €/m ?
  • 100 EUR/m ?
  • EUR 100 /m ?? (seems broken)
  • £100 /m ?? (seems broken)

If 100 €/m (SI) is the way to go, would using SI for currency be still considered as incorrect or could it be accepted even though considered uncommon? (i.e.: 100 €)

  • Try this style guide, it's great: stylemanual.gov.au/grammar-punctuation-and-conventions/…
    – Lambie
    Commented Feb 15 at 17:29
  • Different countries will have different conventions, and even within a single country, you may have differing conventions for different languages (for example, in English-speaking Canada, one writes $100, but in Québec it's 100$. I'd recommend consulting a style guide for the country and language you're writing in. Commented Feb 15 at 17:46
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    @JeffZeitlin As stated in the question we can restrict answers to UK for simplicity.
    – Peque
    Commented Feb 15 at 18:00
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    As a bit of anecdotal evidence, long distance calls in the US always seem to be priced as "75 cents per minute" or "$1.25 per minute" or whatever the price is - the "per minute" appears to always be written out in words, rather than in the slash notation. This might be a reasonable usage for any of your example cases - "£3 per metre" for the metal rod, for example. Commented Feb 15 at 18:16
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    SI compound units often use negative indices rather than 'per' or the solidus. Thus 10ms⁻²; kgm⁻³. No gap before the derived unit (or any other). With currency, there is no corresponding scientific convention. I'd advise a 'per' as in say £4000 per kg (or £4000 / kg) and I prefer a gap where there is no orthography czar. Commented Feb 15 at 19:28

1 Answer 1


As the question correctly points out, every possible way of using slashes in the contexts of this kind is bound to be awkward in some way. The only elegant way of dealing with the matter (where there is no style manual that explicitly covers it) is the one suggested in a comment by Mr Zeitlin, which is to not use slashes at all, but the word per, followed by the unit written out in full: e.g. '$1.25 per minute', '£3 per metre'.

  • Journals and institutions may have style guides, but Zeitlin suggests that countries have style guides, of which I have never seen. (Please show me examples if they do.) In technical fields it is common to use the slash and there is no compelling reason to ditch it in favor of "per". Even with currency symbols, units such as, $/lb, €/m, or CNY/s are commonplace.
    – m_a_s
    Commented Feb 17 at 19:27

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