How to Put Subscript in LaTeX: A Complete Guide

LaTeX handles subscripts with precision that word processors simply can't match — which is exactly why scientists, engineers, and mathematicians rely on it for technical documents. Whether you're writing chemical formulas, mathematical expressions, or indexed variables, knowing how subscript works in LaTeX is a foundational skill.

What Is Subscript in LaTeX?

Subscript refers to text or numbers that appear slightly below the baseline of the main text — like the "2" in H₂O or the "n" in xₙ. In LaTeX, subscripts are primarily used in math mode and are controlled with a single character: the underscore _.

This is different from word processors where you highlight text and click a button. In LaTeX, subscript is a structural command tied to the typesetting engine itself, which gives you far more control and consistency across complex documents.

The Basic Subscript Syntax

The core rule is simple: