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HTML <sub> Tag

The <sub> tag is used to define the subscript text that appears half a character below the line, and is rendered in a smaller font. See examples and Syntax.

The <sub> tag is used to define the subscript text that appears half a character below the line and is rendered in a smaller font. The subscript text can often be used for defining chemical formulas.

You must use the <sub> tag only for typographical reasons. It shouldn’t be used for styling purposes. If you want to change the vertical position of a text, you can use the CSS vertical-align property with the "sub" value.

Tip

To define superscript text, use the <sup> tag.

Syntax

The <sub> tag comes in pairs. The content is written between the opening (<sub>) and closing (</sub>) tags.

Example of the HTML <sub> tag:

HTML <sub> tag

<!DOCTYPE html>
<html>
  <head>
    <title>Title of the document</title>
  </head>
  <body>
    <p>Formula of water - H<sub>2</sub>O, formula of alcohol - C<sub>2</sub>H<sub>5</sub>O</p>
  </body>
</html>
Try it Yourself »

Result

sub example

Example of the HTML <sub> tag used with the <sup> tag:

Example of the HTML <sub> tag with the <sup> tag:

<!DOCTYPE html>
<html>
  <head>
    <title>Title of the document</title>
  </head>
  <body>
    <p>
      The formula of water is H<sub>2</sub>O, and the formula of alcohol is C<sub>2</sub>H<sub>5</sub>O
    </p>
    <p>
      E = mc<sup>2</sup>, where E — kinetic energy, m — mass, c — the speed of light.
    </p>
  </body>
</html>
Try it Yourself »

Example of the HTML <sub> tag used with the CSS vertical-align property:

Example of the HTML<sub> tag with the CSS vertical-align property:

<!DOCTYPE html>
<html>
  <head>
    <title>Title of the document</title>
    <style>
      sub {
        vertical-align: sub;
        font-size: small;
      }
    </style>
  </head>
  <body>
    <h1>Example of the sub tag</h1>
    <p>
      Here is some text <sub>with the sub tag</sub>.
    </p>
    <p>
      Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis ...
    </p>
    <p>
      Reference site about Lorem Ipsum,<sub> giving information on its origins</sub>, as well as a random Lipsum generator.
    </p>
  </body>
</html>
Try it Yourself »

Attributes

The <sub> tag supports the Global attributes and the Event Attributes.

How to style an HTML <sub> tag

sub {
  color: #555;
  font-size: 0.8em;
}

Note: This example overrides the browser's default styling for demonstration purposes.

Practice

Practice

What is the correct usage and syntax for the HTML <sub> tag as per the w3docs.com guide?