How to write subscript(x₂) in LaTeX?

Subscripts are commonly used when creating a document. In this tutorial we will discuss how to use subscripts in LaTeX, both in text mode and math mode.

Use subscript in math mode

Using subscripts in math mode is very easy, you just need to use this character _(underscore). For example if you want to print O₂ then you have to write the syntax like this \[ O_2 \].

\documentclass{article}
\usepackage{amsmath} % For \longrightarrow
\begin{document}
  \[ \verb|H_2 O|\longrightarrow H_2 O \]
  \[ \Lambda_0\quad\Lambda_e\quad\Lambda_\nu \]
  \[ \sum_n \quad \bigcup_m\quad \int_0 \]
  \[ (a_0,a_1,a_2,\dots,a_n) \]
\end{document}

Output :

Use subscript in math mode.

If you want to use more than one character in the subscript, pass the characters in curly brackets {}.

Moreover, the first characters will be printed as subscript and the remaining characters will be printed as normal text.

So if you want to print An+1 then the syntax will be A_{n+1}.

\documentclass{article}
\usepackage{amsmath} % For \longrightarrow
\begin{document}
  \[ \verb|A_n+1|\longrightarrow A_n+1 \]
  \[ \verb|A_{n+1}|\longrightarrow A_{n+1} \]
  \[ \Lambda_{pq}\quad\Lambda_{\mu e}\quad\Lambda_{\nu a} \]
  \[ \sum_{n=1} \quad \bigcup_{m=1}\quad \int_{2\pi} \]
  \[ (a_0,a_1,a_2,\dots,a_{(n-1)},a_n) \]
\end{document}

Output :

Use more than one character as subscript.

Also you can use single dollar to use superscript in inline mode. Like this $O_2$

\documentclass{article}
\begin{document}
  What is $O_2$ used for?\\[4pt]
  What is $H_2 SO_4$ called in chemistry?\\[4pt]
  Summation in Mathematics is denoted by the symbol $ \sum $ and for a set of real numbers $ x_1, x_2, \cdots, x_n $, their sum is defined as $ \sum_{k=1}^{n}x_k $ .  That is
\end{document}

Output :

Use subscript in inline mode.

Subscript in usual text mode

LaTeX provides a default command to use subscripts in the text mode of LaTeX, which is \textsubscript. With this command you can easily use subscript in usual text mode.

\documentclass{article}
\usepackage{amsmath} % For \longrightarrow
\begin{document}
  \verb|A\textsubscript{n-1}|$\longrightarrow$ A\textsubscript{n-1}\\[4pt]
  What is O\textsubscript{2} used for?\\[4pt]
  What is H\textsubscript{2}SO\textsubscript{4} called in chemistry?\\[4pt]
  (a\textsubscript{0},a\textsubscript{1},a\textsubscript{2},$\dots$,a\textsubscript{n-1},a\textsubscript{n})
\end{document}

Output :

Use subscript in usual text mode.

Multiple(double) subscript in LaTeX

If you want to use double subscripts, write the syntax a_{b_c } or {a_b}_c rather than a_b_c .

And if you write like this a_b_c you will get error message. Also you can write triple subscript like this a_{b_{c_d}}.

\documentclass{article}
\usepackage{amsmath} % For \longrightarrow
\begin{document}
  \verb|a_{b_c}|$\longrightarrow a_{b_c}$\\[5pt]
  \verb|{a_b}_c|$\longrightarrow {a_b}_c $\\[5pt]
  \verb|a_{b_{c_d}}|$\longrightarrow a_{b_{c_d}} $\\[5pt]
  \verb|a_{1_{2_{3_{\ddots_{n}}}}}|$\longrightarrow a_{1_{2_{3_{\ddots_{n}}}}} $
\end{document}

Output :

Double subscript in latex.

Md Jidan Mondal

LaTeX expert with over 10 years of experience in document preparation and typesetting. Specializes in creating professional documents, reports, and presentations using LaTeX.

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