\usepackage{latexindent}
How to Format and Beautify LaTeX Code
Messy LaTeX source code is hard to read, harder to debug, and painful to collaborate on. Formatting your .tex files with consistent indentation and clean structure makes everything easier. This guide shows you how to format LaTeX code online using FormaTeX's free formatter, powered by latexindent — no installation required.
Whether you are cleaning up a thesis before submission, enforcing a house style across a multi-author paper, or simply making your source code easier to scan, a LaTeX formatter saves you from doing it by hand. Paste your code, click format, and copy the result.
\section{Why format}
Why format LaTeX code?
LaTeX is a markup language, and like any markup, the source file can quickly become difficult to navigate if formatting is inconsistent. Unlike compiled output, you spend most of your time staring at the source — so its readability directly affects your productivity. Here are the four main reasons to keep your LaTeX code formatted.
Readability
Properly indented LaTeX code lets you see the document structure at a glance. When every \begin and \end pair is visually aligned, you can instantly tell which content belongs to which environment. This is especially important in long documents with deeply nested structures like figures inside subfigures inside columns.
Collaboration
When multiple authors work on the same .tex file, formatting inconsistencies pile up fast. One person uses two-space indentation, another uses tabs, and a third uses no indentation at all. A shared formatting standard — enforced by a tool — eliminates style arguments and keeps diffs clean in version control.
Debugging
The most common LaTeX errors are mismatched braces and missing \end tags. When your code is properly formatted, these problems become visually obvious. An \end{itemize} that is not at the same indentation level as its \begin{itemize} immediately stands out. Without formatting, you are left counting braces by hand.
Consistency
Journals, universities, and research groups often have style guidelines for LaTeX source code. A formatter lets you apply those rules automatically across every file in a project, ensuring that your source code looks the same whether it was written by a first-year student or a senior researcher.
\section{Step by step}
Step-by-step: Format with FormaTeX
FormaTeX runs latexindent server-side, so you do not need to install Perl, TeX Live, or any dependencies on your machine. The entire process takes a few seconds, regardless of file size.
Paste your LaTeX code
Open the FormaTeX LaTeX Formatter tool and paste your unformatted .tex source code into the editor panel on the left. The tool accepts any valid LaTeX — full documents with \documentclass, standalone environments, or even single fragments like a tabular block. There is no file size limit for the free tier, so you can paste an entire thesis chapter if needed.
You can also type directly into the editor if you are writing new LaTeX from scratch and want it formatted as you go.
Click Format
Press the Format button to send your code to the FormaTeX server. The formatter runs latexindent with sensible defaults: it normalizes indentation to consistent spacing, aligns \begin and \end delimiters, removes trailing whitespace, and applies clean brace placement. The operation typically completes in under a second — you will see the formatted output appear in the right panel immediately.
The formatter preserves your comments and does not change any LaTeX commands or content. It only modifies whitespace and indentation.
Copy the formatted output
Review the cleanly formatted LaTeX code in the output panel. The formatter highlights the changes so you can see exactly what was modified. When you are satisfied, click the copy button to place the formatted code on your clipboard, then paste it back into your editor — whether that is VS Code, Overleaf, TeXstudio, or FormaTeX's own online editor. You can also download the formatted file directly.
If you are working in a team, consider running the formatter before every commit to keep your repository clean and diffs minimal.
\section{Under the hood}
What latexindent does under the hood
FormaTeX's formatter is powered by latexindent, the industry-standard Perl script for LaTeX source formatting. It is included with every modern TeX Live and MiKTeX distribution, and it is the same tool used by editors like VS Code (via the LaTeX Workshop extension) and TeXstudio for auto-formatting.
When you press Format on FormaTeX, your code is sent to a server running a full TeX Live installation. The server invokes latexindent with a default configuration that covers the vast majority of use cases. It processes your code in a single pass and returns the result — your source code never touches disk and is deleted from memory immediately after formatting.
The key operations latexindent performs include: normalizing indentation levels for all environments, aligning \begin and \end tags, removing trailing whitespace from every line, standardizing blank line usage between paragraphs, and ensuring consistent brace and bracket placement around command arguments. It understands LaTeX-specific constructs like \if...\fi conditionals, math mode delimiters, and verbatim environments (which are left untouched).
\section{Best practices}
Formatting best practices
A formatter handles the mechanical work, but knowing the principles behind good LaTeX formatting will help you write cleaner code from the start. These best practices apply whether you are using FormaTeX, a local latexindent installation, or formatting by hand.
Use consistent indentation
Pick either two spaces or four spaces per indentation level and stick with it across your entire project. Indent the contents of every environment — document, figure, table, itemize, enumerate, equation, and align. The only exception is the document environment itself, which some authors choose not to indent to avoid pushing all content one level in. Whatever convention you choose, apply it uniformly.
\begin{itemize}
\item First item
\item Second item
\begin{itemize}
\item Sub-item
\end{itemize}
\end{itemize}Keep environments properly nested
Every \begin must have a matching \end at the same indentation level. When environments are nested — a tabular inside a table inside a figure, for example — each level should be indented one step further. This visual nesting makes it trivial to spot mismatched or missing delimiters. If you find yourself more than four or five levels deep, consider extracting the inner content into a separate \input file.
\begin{figure}[h]
\centering
\begin{tabular}{lc}
\toprule
Name & Score \\
\midrule
Alice & 95 \\
\bottomrule
\end{tabular}
\caption{Results}
\end{figure}Write meaningful comments
Use comments to explain why, not what. A comment like "% begin table" above a \begin{table} adds nothing. A comment like "% Grade distribution for Fall 2025 cohort" tells a co-author what the table represents. Place section-level comments on their own line, and use end-of-line comments sparingly. Keep comments at the same indentation level as the code they describe.
% Grade distribution for Fall 2025 cohort
\begin{table}[h]
\centering
\begin{tabular}{lc}
...
\end{tabular}
\end{table}Control line length
Keep lines under 80 to 100 characters. Long lines are hard to read, produce noisy diffs in version control, and break side-by-side editing workflows. Break long sentences at natural points — after punctuation or between clauses. For long command arguments, put each argument on its own line. The LaTeX compiler ignores single line breaks within a paragraph, so splitting lines does not affect the output.
% Bad: one very long line
\caption{The relationship between input voltage and output current measured across a 10k ohm resistor at room temperature}
% Good: broken at natural points
\caption{
The relationship between input voltage
and output current measured across
a 10k ohm resistor at room temperature
}\section{Before and after}
Before and after formatting
Here is a real-world example showing what the FormaTeX formatter does to a typical messy LaTeX file. The content is identical — only the whitespace and indentation change.
\begin{document}
\begin{figure}[h]
\centering
\includegraphics[width=0.8\textwidth]{chart.png}
\caption{Quarterly results for 2025.
This chart shows revenue growth.}
\label{fig:chart}
\end{figure}
\begin{table}[h]
\centering
\begin{tabular}{lcc}
\toprule
Quarter & Revenue & Growth \\
\midrule
Q1 & \$120k & 12\% \\
Q2 & \$145k & 21\% \\
Q3 & \$132k & -9\% \\
\bottomrule
\end{tabular}
\caption{Revenue by quarter}
\end{table}
\end{document}\begin{document}
\begin{figure}[h]
\centering
\includegraphics[width=0.8\textwidth]{chart.png}
\caption{
Quarterly results for 2025.
This chart shows revenue growth.
}
\label{fig:chart}
\end{figure}
\begin{table}[h]
\centering
\begin{tabular}{lcc}
\toprule
Quarter & Revenue & Growth \\
\midrule
Q1 & \$120k & 12\% \\
Q2 & \$145k & 21\% \\
Q3 & \$132k & -9\% \\
\bottomrule
\end{tabular}
\caption{Revenue by quarter}
\end{table}
\end{document}Notice how each environment is indented one level within its parent. The \caption with a long argument is broken onto multiple lines. Blank lines separate logical blocks. The content and commands are unchanged — only the structure is clarified.
\section{When to format}
When should you format your LaTeX?
There is no wrong time to format, but some moments are more impactful than others. Format your code before committing to version control — this keeps your git diffs focused on content changes rather than whitespace noise. Format before submitting a paper to a journal, so reviewers and typesetters see clean source. Format when you receive a co-authored file from someone else, to normalize their style to yours.
If you use the FormaTeX API, you can integrate formatting into a CI/CD pipeline or a pre-commit hook. This way, every .tex file in your repository is automatically formatted before it reaches the main branch — similar to how Prettier works for JavaScript or Black works for Python.
\section{Related guides}
Related guides and tools
Explore more LaTeX tools and learn guides on FormaTeX.