Move chapter label position upward

Question

\documentclass[a4paper,12pt]{report}
\usepackage[margin=2.5cm]{geometry}
\usepackage{titlesec}

\begin{document}
\chapter*{Introduction}
Lorem...
\chapter{Lorem}
\section{Lorem Ipsum}
Lorem...
\section{Lorem Ipsum}
Lorem...
\end{document}

Each chapter starts at a new page. And at the begining of a new chapter either I use \chapter*{} or \chapter{}, there is a huge vertical space upwards. How could I reduce that space?

Answer 1

Just use

\titleformat{\chapter}[display]
{\normalfont\huge\bfseries\vskip -30pt}{\chaptertitlename \thechapter}{20pt}{\Huge}

You also need to add \usepackage{titlesc}

If you want to move it even more use -40pt

Answer 2

titlesec also offers the function \titlespacing

\documentclass[a4paper,12pt]{report}
\usepackage[margin=2.5cm]{geometry}
\usepackage{titlesec}

\titleformat{\chapter}%
    [display]% display, hang, runin, block
    {\huge\bfseries}% Format
    {\chaptertitlename{} \thechapter}% Label
    {10pt}% Label - Title spacing
    {}% pre-code
    []% post-code

\titlespacing{\chapter}%
    {0pt}% Left margin
    {4pt}% Pre spacing
    {12pt}% Post spacing
    [0pt]% Right margin}

\begin{document}
\chapter*{Introduction}
Lorem...
\chapter{Lorem}
\section{Lorem Ipsum}
Lorem...
\section{Lorem Ipsum}
Lorem...
\end{document}

In this case, you need to tweak the pre spacing (3rd argument)

Answer 3

Add the following lines in your preamble

\usepackage{tocloft}
\setlength{\cftbeforetoctitleskip}{-1\baselineskip}
\setlength{\cftaftertoctitleskip}{0in}

You can tweak the spacing.