<sub>: The Subscript element #

::: section-content The <sub> HTML element specifies inline text which should be displayed as subscript for solely typographical reasons. Subscripts are typically rendered with a lowered baseline using smaller text. :::

Try it #

::: section-content ::: iframe ::: {.output-header .border-rounded-top}

HTML Demo: <sub> #

Reset :::

::: {#warning-no-script .warning-container} ::: warning The interactive example cannot be shown because JavaScript is disabled. ::: :::

::: {#warning-mathml-not-supported .warning-container .hidden} ::: warning The interactive example cannot be shown because MathML is not supported by your browser. ::: :::

::: {#editor-container .editor-container .tabbed-shorter .hidden .border-rounded-bottom editor-type=“tabbed”} ::: {#tab-container .section .tabs} ::: {#tablist .tab-list role=“tablist”} HTML

CSS

JavaScript :::

::: {#html-panel .section .hidden tabindex=“0” role=“tabpanel” aria-labelledby=“html” aria-hidden=“true”} ::: {#html-editor}

Almost every developer’s favorite molecule is C₈H₁₀N₄O₂, also known as “caffeine.”

::: {#css-panel .section .hidden tabindex=“0” role=“tabpanel” aria-labelledby=“css” aria-hidden=“true”} ::: {#css-editor} p { font: 1rem ‘Fira Sans’, sans-serif; } ::: :::

::: {#js-panel .section .hidden tabindex=“0” role=“tabpanel” aria-labelledby=“js” aria-hidden=“true”} ::: {#js-editor} ::: ::: :::

::: {#output .output-container}

Output #

::: :::

::: {.section .console-container .hidden aria-hidden=“true”}

Console Output #

![] clear console

::: {#console .console} ::: :::

::: {#html-output .output .editor-tabbed} %html-content% ::: ::: :::

Attributes #

::: section-content This element only includes the global attributes. :::

Usage notes #

::: section-content The <sub> element should be used only for typographical reasons—that is, to change the position of the text to comply with typographical conventions or standards, rather than solely for presentation or appearance purposes.

For example, using <sub> to style the name of a company which uses altered baselines in their wordmark{target="_blank"} would not be appropriate; instead, CSS should be used. For example, you could use the vertical-align property with a declaration like vertical-align: sub or, to more precisely control the baseline shift, vertical-align: -25%.

Appropriate use cases for <sub> include (but aren't necessarily limited to):

• Marking up footnote numbers. See Footnote numbers for an example.
• Marking up the subscript in mathematical variable numbers (although you may also consider using a MathML formula for this). See Variable subscripts.
• Denoting the number of atoms of a given element within a chemical formula (such as every developer's best friend, C ~8~ H ~10~ N ~4~ O ~2~ , otherwise known as "caffeine"). See Chemical formulas. :::

Examples #

Footnote numbers #

::: section-content Traditional footnotes are denoted using numbers which are rendered in subscript. This is a common use case for <sub>:

::: code-example [html]{.language-name}

<p>
  According to the computations by Nakamura, Johnson, and Mason<sub>1</sub> this
  will result in the complete annihilation of both particles.
</p>

:::

Result #

::: {#sect1 .code-example} ::: iframe ::: ::: :::

Variable subscripts #

::: section-content In mathematics, families of variables related to the same concept (such as distances along the same axis) are represented using the same variable name with a subscript following. For example:

::: code-example [html]{.language-name}

<p>
  The horizontal coordinates' positions along the X-axis are represented as
  <var>x<sub>1</sub></var> … <var>x<sub>n</sub></var>.
</p>

:::

Result #

::: {#sect2 .code-example} ::: iframe ::: ::: :::

Chemical formulas #

::: section-content When writing a chemical formula, such as H~2~0, the number of atoms of a given element within the described molecule is represented using a subscripted number; in the case of water, the subscripted "2" indicates that there are two atoms of hydrogen in the molecule.

Another example:

::: code-example [html]{.language-name}

<p>
  Almost every developer's favorite molecule is
  C<sub>8</sub>H<sub>10</sub>N<sub>4</sub>O<sub>2</sub>, which is commonly known
  as "caffeine."
</p>

:::

Result #

::: {#sect3 .code-example} ::: iframe ::: ::: :::

Technical summary #

::: section-content

Specifications #

::: _table #

Specification #

HTML Standard
[# the-sub-and-sup-elements]{.small}

:::

Browser compatibility #

::: _table Desktop Mobile

      Chrome    Edge   Firefox   Internet Explorer   Opera   Safari   WebView Android   Chrome Android   Firefox for Android   Opera Android   Safari on IOS   Samsung Internet

sub 1 12 1 Yes 15 ≤4 4.4 18 4 14 ≤3.2 1.0 :::

See also #

::: section-content

• The <sup> HTML element that produces superscript. Note that you cannot use sup and sub both at the same time: you need to use MathML to produce both a superscript directly above a subscript next to the chemical symbol of an element, representing its atomic number and its nuclear number.
• The <msub>, <msup>, and <msubsup> MathML elements.
• The CSS vertical-align property. :::

::: _attribution © 2005–2023 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/HTML/Element/sub{._attribution-link} :::