How to correctly write the thousands separator in American English?

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!

• 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: $10\,000$ Nov 21, 2018 at 2:08
• you can use numprint package with option autolanguage (assuming you use babel with american or USenglish class option)
– user4686
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 ? Nov 21, 2018 at 16:16

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):

Code:

\documentclass{article}
\usepackage{siunitx}

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

$10\,000$: Manual Spacing

\sisetup{group-separator={,}}
\num{10000}: In case you decide you want the comma

\end{document}