Possible Duplicate:
How to specify font size less than 10pt (or more than 12pt)?
Many questions in this matter has been posted and most of the answers are related to either using KOMA-script class or using XeTeX, or using the \documentclass{extreport} which doesn't have a 13pt. So if a report class with default font size of 13pt is required, what should I do?
KOMA-Scriptclass -- using thescrextendpackage will do. See my answer to http://tex.stackexchange.com/questions/30693/making-default-font-size-16pt – lockstep Oct 28 '12 at 12:39\fontsize{13}{15.6}\selectfontwhere13ptis the font size and15.6ptis the baseline skip (which is nearly 120% of fontsize). But you have to use proper fonts that can be scaled. – Oct 28 '12 at 12:52\usepackage{lmodern}. – lockstep Oct 28 '12 at 14:08