If your output is the wrong size, and you’ve checked that it’s not due to the ministrations of Adobe Reader, the problem is probably that your (La)TeX system is producing output that specifies the wrong paper size. Paper sizes can be a pain: they’re a forgotten backwater — Knuth seems not to have considered paper size as something the TeX engine needs to know about. As a result, there is no DVI command to specify the paper on which the document should be printed, which has led a dichotomy where macros shape the text according to the needs of the author’s chosen paper size, and device drivers’ choice happens independently of the macros’ ideas.
In practice, one usually finds that macro packages (such as Plain TeX and LaTeX) assume American “letter” paper size, by default; and since most distributions nowadays originate in Europe, the drivers usually default to ISO “A4” paper size.
This is (of course) pretty unsatisfactory. Users may select a different paper size for their document (current LaTeX offers a range of sizes as options in the standard classes), pretty easily. Nevertheless, the user also has to be sure that each time xdvi, dvips (or whatever) runs, it uses the paper size the document was designed for.
The default paper size for DVI drivers may be changed by a distribution management command (texconfig for texlive, the Options application for MiKTeX), but this still doesn’t provide for people using the “wrong” sort of paper for some reason.
A different issue arises for users of PDFTeX — the
PDF format does have the means of expressing paper size
and PDFTeX has system variables \pdfpagewidth and
\pdfpageheight, that are written into the output PDF file.
Unfortunately, most of the core software predates PDFTeX, so not even
PDFLaTeX sets the correct values into those variables, to match the
paper size specified in a \documentclass option.
The DVI drivers dvips, dvipdfm and its
extensions (dvipdfmx and xdvipdfmx) define
\special commands for the document to specify its own paper size;
so in those cases, as when PDFTeX is being used, the
paper size can be programmed by the document. Users who wish to, may
of course consult the manuals of the various programs to write the
necessary code.
The geometry and zwpagelayout packages (whose main
business includes defining
typeset page areas), also takes notice the size of the paper that the
document is going to be printed on, and can issue the commands
necessary to ensure the correct size of paper is used. If
geometry is used when a document is being processed by
PDFLaTeX, it can set the necessary dimensions “in the output”.
If the document is being processed by LaTeX on a TeX or e-TeX
engine, there are package options which instruct geometry
which \special commands to use. (Note that the options are
ignored if you are using PDFLaTeX.)
So, one resolution of the problem, when you are using LaTeX, is to add
\usepackage[processor-option,...]{geometry}
Where processor-option tells the package what will produce
your (PostScript or PDF output — geometry knows about
dvips and dvipdfm (dvipdfm also
serves for the extension dvipdfmx and
xdvipdfmx).
If you’re using PDFLaTeX or XeTeX, load with
\usepackage[program-option,...]{geometry}
where program-option is pdftex,
xetex.
The alternative, zwpagelayout requires a driver
option:
\usepackage[driver=value,...]{zwpagelayout}
(permissible ‹values› are pdftex, xetex
and dvips; the default value is unknown).
Needless to say, both the “big” classes (koma-script and memoir) provide their own ways to get the paper size “right”.
The typearea package is the Koma-script
distribution’s way of providing page layout functionality. Load it
with the pagesize option and it will ensure the correct
paper is selected, for PDF output from PDFLaTeX, and for
PostScript output from LaTeX via dvips.
Memoir has the standard classes’ paper-size selections
(a4paper, letterpaper and so on), but also
permits the user to choose an arbitrary paper size, by setting the
length registers \stockheight and \stockwidth. The commands
\fixdvipslayout (for LaTeX processing), and \fixpdflayout
(for PDFLaTeX processing) then instruct the processor to produce
output that specifies the necessary paper size.
This answer last edited: 2011-12-12
This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=papergeom