How to Write Subscript in LaTeX: A Complete Guide

Subscript notation is one of the most frequently used formatting tools in LaTeX — whether you're writing chemical formulas, mathematical expressions, or technical documentation. LaTeX handles subscript through a clean, consistent syntax, but the specifics shift depending on your environment, nesting needs, and document type.

What Is Subscript in LaTeX?

In LaTeX, subscript refers to text or characters positioned slightly below the baseline of the main text — like the "2" in H₂O or the "n" in xₙ. LaTeX was designed with scientific and mathematical typesetting at its core, so subscript support is built directly into the language rather than bolted on as an afterthought.

The Core Subscript Syntax

The fundamental operator for subscript in LaTeX is the underscore character _.