%%
%% The LaTeX Companion, 2ed (second printing August 2004)
%%
%% Example A-1-13 on page 856.
%%
%% Copyright (C) 2004 Frank Mittelbach, Michel Goossens,
%%    Johannes Braams, David Carlisle, and Chris Rowley
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3
%% of this license or (at your option) any later version.
%%
%% See http://www.latex-project.org/lppl.txt for details.
%%

\documentclass{ttctexa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{135.0pt}
\StartShownPreambleCommands
\newlength\Mylen    \raggedright% to make example nicer
\StopShownPreambleCommands
\begin{document}
\settowidth \Mylen{Typography} width  = \the\Mylen \\
\settoheight\Mylen{Typography} height = \the\Mylen \\
\settodepth \Mylen{Typography} depth  = \the\Mylen \par
Use larger font and recalculate: \\
\settowidth\Mylen{\large Typography} width = \the\Mylen
\end{document}