# Formatting Chapter Titles

I'm working on my thesis, and I need my chapter titles to be centered so it says "CHAPTER " and then immediately under it the actual chapter title. Right now I have

\titleformat{\chapter}{\normalfont \center}{CHAPTER \thechapter}{}{}

but I can't figure out how to get the new line to work, as

\titleformat{\chapter}{\normalfont \center}{CHAPTER \thechapter \\}{}{}

fails to compile.

To center, the package offers you \filcenter; the fourth mandatory argument cannot be empty (it requires some length, even 0pt); this argument controls the vertical separation (since display format is used) between the label "Chapter #" and the actual title. No need to explicitly write "CHAPTER"; you can use \MakeUppercase{\chaptertitlename}. Adjust the settings according to your needs:

\documentclass{book}
\usepackage{titlesec}
\usepackage{lipsum}

\titleformat{\chapter}[display]
{\normalfont\filcenter}{\MakeUppercase{\chaptertitlename}~\thechapter}{10pt}{}

\begin{document}

\chapter{Test Chapter}
\lipsum[1-4]

\end{document}