HTML <sub> Tag

The <sub> tag is used to display text as subscript. Subscript is text that is smaller and appears lower than regular text.

HTML Tag

Example

#

A <sub> element that displays a subscripted number 2.

The formula for water is H2O.

<p>
  The formula for water is H<sub>2</sub>O.
</p>
sub = subscript

Using <sub>

The <sub> tag is used to display subscript text.

Subscript text is displayed half a character below the baseline and displayed using smaller font.

The <sub> element can be used to write chemical or mathematical formulas.

More Examples

With just the <sup> and <sub> elements you can write complex chemical formulas.

The formula for Hexamminecobalt chloride is [Co(NH3)6]3+Cl3−

<p>
    The formula for Hexamminecobalt chloride is 
    [Co(NH<sub>3</sub>)<sub>6</sub>]<sup>3+</sup>Cl<sup>3−</sup>
</p>


Attributes for <sub>

The <sub> element has no attributes, but it does accept global attributes.
The following are commonly used.

Attribute Value Description
id    value Provides the sub element with a unique identifier.
class    classnames Assigns one or more classnames to the sub element.
style    CSS-values Assigns CSS style values to the sub element.

For additional global attributes see our global attributes list.


Text Tags

The <sub> tag is part of a group of tags that are used to create and format text documents. This group is referred to as the Text tag group. Together, these tags allow you to create comprehensive HTML text documents.

Here is a list of text tags.

Element Description
<h1>-<h6> Defines text headings in 6 different sizes
<p> Creates a paragraph
<span> Container for one or more inline text elements
<br> Creates a line break
<sup> Specifies superscript text
<sub> Specifies subscripted text
<u> Specifies underlined text
<i> Specifies italic text
<b> Specifies bold text
<em> Marks text that needs emphasis
<strong> Indicates text that is important or with high urgency
<del> Defines deleted text
<ins> Defines inserted text
<ruby> Represents a small annotation with pronunciation of text
<kbd> Specifies keyboard input, such as, CTRL or ALT
<wbr> Specifies a preferred word-break location for long words

Browser support

Here is when <sub> support started for each browser:

Chrome
1.0 Sep 2008
Firefox
1.0 Sep 2002
IE/Edge
1.0 Aug 1995
Opera
1.0 Jan 2006
Safari
1.0 Jan 2003

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