[Tex/LaTex] \columnwidth in cm

Question

I have a silly question – i am using double column style

\documentclass[english,a4paper,12pt, openany]{book}

When I add a figure I usually put in \columnwidth and just let LaTeX to stretch it to the full width. Now, for practical reasons I'd like to prepare some figures with fixed width in 1:1 ratio, but for that I'd like to know what the \columnwidth is in cm.
Is there a way to find that number?

thanks,
U

Answer 1

The xprintlen package provides the means to show the length of a dimension register in more 'human' units, such as cm or mm, which is the default:

\printlen[2][mm]{length register}

Will use 2 significant figures (which is the default), mm as unit of the relevant length register.

\documentclass{article}
\usepackage{pgffor}
\usepackage{xprintlen}

\begin{document}
\foreach \x in {1,...,5} {%
\printlen[\x][cm]{\columnwidth}

}
\end{document}