# What unit of measurement is \widthof using

For various purposes I need to know the width of a given text. The easiest way to do this is to use the \widthof{} command from the calc package. Issue is that I can't understand what unit of measurement is this command using. I expected it to be pt, but the number gets so big that it can't possibly be that.

The following MWE, for instance, will print the value 2081098:

\documentclass[11pt, a4paper]{article}

\usepackage{calc}

\newcounter{a}

\begin{document}

\setcounter{a}{\widthof{asdasd}}
\thea

\end{document}


The package documentation doesn't indicate the unit of measurement.

• Scaled points; 65536sp=1pt. But why using a counter? If \mylen is a length, \settowidth{\mylen}{asdasd} would store the width more easily. – egreg Mar 21 '17 at 13:14
• this is nothing to do with \widthof, it is how any length is cast to a counter, try \setcounter{a}{\textwidth} for example. – David Carlisle Mar 21 '17 at 13:19
• I was totally noob on the lengths matter. Now I see how to use them. Thanks everybody – il mietitore Mar 21 '17 at 14:17

When you do

\documentclass[11pt]{article}

\newlength{\mylen}
\newcounter{a}

\begin{document}

\settowidth{\mylen}{asdasd}

\the\mylen

\setlength{\mylen}{\widthof{asdasd}}

\the\mylen

\end{document}


you get

31.75504pt
31.75504pt

\setcounter{a}{\mylen}
\thea


you get

2081098

because

31.75504 * 65536 = 2081098.30144


and TeX truncates this to an integer. The dimension in points is coerced to scaled points (65536sp = 1pt).