Determine text width

Question

For sizing figures in LaTeX it's helpful to know how wide the text is so that figures can be sized to match without rescaling. LaTeX provides \textwidth for reference by other commands, e.g.
\includegraphics[width=\textwidth]{figure}
but including \textwidth "raw" in the document produces errors.

Is there a way to determine what this value is?

Answer 1

From http://www.latex-community.org/forum/viewtopic.php?f=5&t=2712

Using \the\textwidth will allow you to see the value LaTeX is using. However, the default unit of measurement is probably points, not a likely option for your graphics software.

Fortunately, the conversion function is available in the standard layouts package: \usepackage{layouts}
...
textwidth in cm: \printinunitsof{cm}\prntlen{\textwidth}
will print the value in cm. All the usual LaTeX units of measurement are also available if cm aren't what you want.

Answer 2

The printlen package:

\documentclass{article}
\usepackage{printlen}
\begin{document}
\printlength\textwidth
\end{document}

produces "345.0pt". It can print in units other than pt, too.

Answer 3

Here is an option with pgf

% !Mode:: "TeX:UTF-8"
\documentclass{article}
\usepackage{pgf}

\begin{document}
\noindent
\the\textwidth \\
\pgfmathparse{\textwidth}
\pgfmathresult pt \\
\end{document}

where \pgfmathparse returns \textwidth in points but without unit to \pgfmathresult, so you have to manually add unit to it

however you know it is always in points.

Answer 4

I encountered the same challenge. However, I did not manage to use the abovementioned options. My LaTeX distribution did not recognized \printinunitsof as a valid statement.

What worked perfectly fine for me was to take a screen shot of the PDF and measure the width of the text and the width of the document in pixels using a programme like Paint. As the total document width in cm is known, you can calculate:

textwidth_cm = documentwidth_cm*textwidth_pixels/document_pixels

The textwidth is also equal to the documentwidth minus the left and right margins. If you explicitly specify the margins (e.g. with the geometry package), the textwidth is also easily calculated.