% https://tex.stackexchange.com/questions/50258/margins-of-book-class
\documentclass{book}
\usepackage{layout}
\begin{document}
\layout
\end{document}
% kirajzolja a lap méreteit.
Ez meg a méreteket is kiírja cm-ben:
\documentclass{article}
\usepackage{geometry}
\usepackage{layouts}
\usepackage{layout}
\printinunitsof{cm}
\begin{document}
\pagevalues
\newpage
\layout
\end{document}