.tex

What is a .tex file?

TEX is a LaTeX source file — the typesetting language academics use for papers, theses, and anything with equations.

Safe format
Type Document
By Leslie Lamport / Donald Knuth
MIME application/x-tex

Drop any file to identify it

No upload. No signup. No sending your file halfway across the internet.
We tell you what it is, right here in your browser.

What is it

LaTeX is how serious academic writing gets done. A .tex file is plain text sprinkled with markup commands — `\section{}`, `\begin{equation}`, `\cite{}` — that a LaTeX compiler transforms into immaculately typeset PDF output. The learning curve is a cliff, but the results are unmatched: no word processor handles mathematical notation, cross-references, and bibliography management as gracefully.

The format has been the standard for scientific publishing since the 1980s. Physics, mathematics, computer science, and economics journals overwhelmingly accept (or require) LaTeX submissions. If you've read an academic paper with beautiful equations, it was almost certainly written in LaTeX.

You don't "open" a .tex file for viewing — you compile it. Install a TeX distribution (TeX Live, MiKTeX) and run `pdflatex` to produce a PDF. For a friendlier experience, Overleaf (free, browser-based) handles compilation, collaboration, and templates without local installation. VS Code with the LaTeX Workshop extension is the best desktop editor.

Technical details
Full Name
LaTeX Source Document
MIME Type
application/x-tex
Developer
Leslie Lamport / Donald Knuth
Magic Bytes
N/A
Safety
.tex is a known, safe format. Plain text file. Cannot contain executable code directly, though compilation may invoke system commands.
What opens it
Overleaf
FREE Web
VS Code (+ LaTeX Workshop)
FREE Windows / Mac / Linux
TeXstudio
FREE Windows / Mac / Linux
FAQ
How do I open a .tex file?
Open it in any text editor to read the source. To produce the formatted document, compile it with a LaTeX engine (pdflatex, xelatex) or use Overleaf (free, browser-based) which handles compilation automatically.
Is LaTeX hard to learn?
The basics (sections, paragraphs, simple formatting) take an afternoon. Equations, bibliographies, and custom layouts take longer. Overleaf's templates make it much easier — start from a working example rather than a blank file.
Why do academics use LaTeX instead of Word?
Superior equation typesetting, automatic numbering and cross-references, robust bibliography management, consistent output across systems, and journal submission requirements. The tradeoff is a steeper learning curve.
Related formats