I am not a native speaker and I must write a scientific document in American English. How would you correctly write "10000" using LaTeX ?

  1. with a space only (10 000): $10\,000$
  2. with a coma and no space in either side (10,000): $10{,}000$
  3. with a coma and a space on its right (10, 000) : $10,000$

I have seen the second a few times, but I do not know if there is a consensus. Thanks for your help!

  • 6
    I would recommend that you use the siunitx package and then \num{10000}. That way you can always change it later. Without siunitx, I would use the first option your suggest: $10\,000$ Commented Nov 21, 2018 at 2:08
  • 1
    you can use numprint package with option autolanguage (assuming you use babel with american or USenglish class option)
    – user4686
    Commented Nov 21, 2018 at 8:33
  • @PeterGrill thanks a lot, I think I will go on with this for now. Could you propose it as an answer so I can accept it ?
    – jeannej
    Commented Nov 21, 2018 at 16:16
  • For the record, as an American, the thin space is well-known and understood in technical fields, but almost unheard-of in the general population. (No idea about business contexts). I would guess that the thin space would be understood even by those who had never seen it before in most contexts, though, especially if the context made it clear that a single number was expected (particularly one of that magnitude). The comma is vastly more common, even in technical fields, and ubiquitous in the general population. There is never a space after the comma used as a separator.
    – KRyan
    Commented Nov 20, 2022 at 18:08

1 Answer 1


My recommendation would be to use siunitx's \num{} macro (which by default will add a \thinspace, but can be configured to add a comma if so desired):

enter image description here




\num{10000}: Recommended (Using \verb|\num{}|)

$10\,000$: Manual Spacing

\num{10000}: In case you decide you want the comma


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