# “12,345” and “1.234,5” with siunitx

\num{12345} formats as "12,345". That looks right. I want that thousands separator.

\num{1.2345} formats as "1.234,5". I'm not used to seeing the comma group separator used after the decimal like that. Is that normal? Can I disable that, while keeping it before the decimal point?

Option group-digits=integer helps to get groups for the integer part only:

\documentclass{article}
\usepackage{siunitx}
\sisetup{
group-separator={,},
group-minimum-digits=4,% or group-four-digits
group-digits=integer,
}

\begin{document}
\num{12345}
\num{1.2345}
\end{document}