Change size of section, subsection, subsubsection, paragraph and subparagraph title

I would like to increase the size of pretty much every headlines, so that it is more prominent than the normal text.

I read about the titlesec package, but can't seem to find good example how to use the package.

Using Gonzalo Medina does in fact change the font size, however, it changes the default font as well.

Before:

After:

Standard classes

Here's an exaple using titlesec:

\documentclass{article}
\usepackage{titlesec}

\titleformat*{\section}{\LARGE\bfseries}
\titleformat*{\subsection}{\Large\bfseries}
\titleformat*{\subsubsection}{\large\bfseries}
\titleformat*{\paragraph}{\large\bfseries}
\titleformat*{\subparagraph}{\large\bfseries}

\begin{document}

\section{Test section}
\subsection{Test section}
\subsubsection{Test section}
\paragraph{Test section}
\subparagraph{Test section}

\end{document}

I used the simplified version of \titleformat (i.e., \titleformat*) since the only desired change was in size, but you can use the extended version if "bigger" changes are required. These are the default definitions for the standard classes (taken from the documentation):

\titleformat{\section}
{\normalfont\Large\bfseries}{\thesection}{1em}{}
\titleformat{\subsection}
{\normalfont\large\bfseries}{\thesubsection}{1em}{}
\titleformat{\subsubsection}
{\normalfont\normalsize\bfseries}{\thesubsubsection}{1em}{}
\titleformat{\paragraph}[runin]
{\normalfont\normalsize\bfseries}{\theparagraph}{1em}{}
\titleformat{\subparagraph}[runin]
{\normalfont\normalsize\bfseries}{\thesubparagraph}{1em}{}

so you can make bigger changes. The following image shows both the standard sizes and the ones obtained with the above modifications:

And here's an exampe using the sectsty:

\documentclass{article}
\usepackage{sectsty}

\sectionfont{\LARGE}
\subsectionfont{\Large}
\subsubsectionfont{\large}
\paragraphfont{\large}

\begin{document}

\section{Test section}
\subsection{Test section}
\subsubsection{Test section}
\paragraph{Test section}
\subparagraph{Test section}

\end{document}

According to an edit to the original question, the OP wanted also a sans serif font:

\documentclass{article}
\usepackage{titlesec}

\titleformat*{\section}{\LARGE\bfseries\sffamily}
\titleformat*{\subsection}{\Large\bfseries\sffamily}
\titleformat*{\subsubsection}{\large\bfseries\sffamily}
\titleformat*{\paragraph}{\large\bfseries\sffamily}
\titleformat*{\subparagraph}{\large\bfseries\sffamily}

\begin{document}

\section{Test section}
\subsection{Test section}
\subsubsection{Test section}
\paragraph{Test section}
\subparagraph{Test section}

\end{document}

KOMA classes

The above approaches are to be used mostly with the default document classes (book, report, article); if the document class used is one of the classes of the KOMA-Script bundle, then it's not advisable to use titlesec (See Incompatibilities between KOMA-Script and titlesec) but to use the features provided by the KOMA classes:

\documentclass{scrartcl}

\setkomafont{section}{\LARGE}
\setkomafont{subsection}{\Large}
\setkomafont{subsubsection}{\large}
\setkomafont{paragraph}{\large}
\setkomafont{subparagraph}{\large}

\begin{document}

\section{Test section}
\subsection{Test section}
\subsubsection{Test section}
\paragraph{Test section}
\subparagraph{Test section}

\end{document}

memoir

For the memoir document class, the situation is analogous: is also not advisable to use titlesec (See About memoir and titlesec incompatibility) but to use the features provided by the class; in the case of the lower sectional units, the class provides the family of commands \setXheadstyle:

\documentclass[article]{memoir}

\begin{document}

\section{Test section}
\subsection{Test section}
\subsubsection{Test section}
\paragraph{Test section}
\subparagraph{Test section}

\end{document}
• Thanks. Works pretty good, except for the first modification. Because changing the size without further options, it changes to a different font. – cherrung Jun 13 '12 at 21:49
• @cherrung: How about just adding \sffamily to the list of corrections? – Werner Jun 13 '12 at 22:22
• @cherrung as Werner said, simply add \sffamily, as I did in the last code of my updated answer. – Gonzalo Medina Jun 13 '12 at 22:43
• @cherrung which document class are you using? The standard classes don't use a sans-serif font by default, so your last requirement makes me wonder if you are using some non-standard document class. – Gonzalo Medina Jun 13 '12 at 22:54
• @cherrung that is crucial information that you should have mentioned in your original question. KOMA-Script and titlesec are incompatible, so titlesec is not advisable here; I've provided an example on how to proceed with the KOMA classes in my updated answer. – Gonzalo Medina Jun 13 '12 at 23:35

You can just modify the sectional commands with the appropriate font size. Here's a small example in the article document class:

\documentclass{article}
\begin{document}
\section{A section}
\subsection{A subsection}
\subsubsection{A subsubsection}

\makeatletter
\renewcommand\section{\@startsection {section}{1}{\z@}%
{-3.5ex \@plus -1ex \@minus -.2ex}%
{2.3ex \@plus.2ex}%
{\normalfont\LARGE\bfseries}}% from \Large
\renewcommand\subsection{\@startsection{subsection}{2}{\z@}%
{-3.25ex\@plus -1ex \@minus -.2ex}%
{1.5ex \@plus .2ex}%
{\normalfont\Large\bfseries}}% from \large
\renewcommand\subsubsection{\@startsection{subsubsection}{3}{\z@}%
{-3.25ex\@plus -1ex \@minus -.2ex}%
{1.5ex \@plus .2ex}%
{\normalfont\large\bfseries}}% from \normalsize
\makeatother

\section{A section}
\subsection{A subsection}
\subsubsection{A subsubsection}

\end{document}

For a different font, replace \normalfont with the appropriate definition. For example, using \sffamily will yield:

titlesec package options

For simple cases, you can use \usepackage[<size>]{titlesec}, where <size> is big, medium, small, or tiny.

Example code

\documentclass{article}

\usepackage[medium]{titlesec}

\begin{document}
\section{A section}
\subsection{A subsection}
\subsubsection{A subsubsection}
\end{document}

For completeness I'll give a ConTeXt solution also.

You can change the heading style using:

The font switch \tf equals the body fontsize, \tfa is 1.2 times \tf; \tfb is 1.2 times \tfa and so on. If you want sans serif headings, then use