Fixed-width tables

There are two basic techniques for making fixed-width tables in LaTeX: you can make the gaps between the columns stretch, or you can stretch particular cells in the table.

Basic LaTeX can make the gaps stretch: the tabular* environment takes an extra argument (before the clpr layout one) which takes a length specification: you can say things like "15cm" or "\columnwidth" here. You must also have an \extracolsep command in the clpr layout argument, inside an @ directive. So, for example, one might have

\begin{tabular*}{\columnwidth}{@{\extracolsep{\fill}}lllr}
The \extracolsep applies to all inter-column gaps to its right as well; if you don't want all gaps stretched, add \extracolsep{0pt} to cancel the original.

The tabularx package defines an extra clpr column specification, X; X columns behave as p columns which expand to fill the space available. If there's more than one X column in a table, the spare space is distributed between them.

The tabulary package (by the same author) provides a way of "balancing" the space taken by the columns of a table. The package defines column specifications C, L, R and J, giving, respectively, centred, left, right and fully-justified versions of space-sharing columns. The package examines how long each column would be "naturally" (i.e., on a piece of paper of unlimited width), and allocates space to each column accordingly. There are "sanity checks" so that really large entries don't cause everything else to collapse into nothingness (there's a "maximum width" that any column can exert), and so that tiny entries can't get smaller than a specified minimum. Of course, all this work means that the package has to typeset each row several times, so things that leave "side-effects" (for example, a counter used to produce a row-number somewhere) are inevitably unreliable, and should not even be tried.

The ltxtable combines the features of the longtable and tabularx packages: it's important to read the documentation, since usage is distinctly odd.

ltxtable.sty
Distributed as part of macros/latex/contrib/carlisle (zip, browse)
tabularx.sty
Distributed as part of macros/latex/required/tools (zip, browse)
tabulary.sty
Distributed as part of macros/latex/contrib/carlisle (zip, browse)

This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=fixwidtab