Square Brackets in LaTeX (\left[ x \right])

Where it is used

Square brackets that scale to fit their contents, for grouping, commutators or closed intervals.

Square brackets serve as the next level of grouping outside parentheses, the closed interval [a, b], the commutator [A, B] = AB - BA, the expectation \mathbb{E}[X], and matrices. With \left[ ... \right] the brackets stretch around fractions, integrals or matrices, as in \left[ \frac{x^2}{2} \right]_0^1 for evaluated antiderivatives. Inside a bmatrix environment the brackets are already provided, so you do not need \left[ yourself. For nested brackets in a long expression, manual sizes like \Bigl[ ... \Bigr] give finer control.

Minimal compilable example

Paste this into an empty .tex file and compile it with pdfLaTeX, XeLaTeX or LuaLaTeX.

\documentclass{article}
\begin{document}
Square Brackets: $\left[ x \right]$

\[ \left[ \frac{x^3}{3} \right]_0^1 = \frac{1}{3} \]
\end{document}

Related symbols

• Curly Braces\left\{ x \right\}
• Parentheses\left( x \right)
• Vertical Bar\left| x \right|
• Double Brackets\llbracket x \rrbracket
• Big Parentheses\Big( x \Big)
• Double Bracket Right\rrbracket

Frequently asked questions

How do I write Square Brackets in LaTeX?

Type \left[ x \right] in math mode, for example $\left[ \frac{x^3}{3} \right]_0^1 = \frac{1}{3}$. It works in plain LaTeX without loading any package.

Which package do I need for \left[ x \right]?

None. \left[ x \right] is part of standard LaTeX, so it compiles with nothing in the preamble but the document class.

Can I use \left[ x \right] in text mode, or only in math mode?

Only in math mode. Outside $...$ LaTeX stops with "Missing $ inserted", so write $\left[ x \right]$ in running text.