Web/CSS/text-underline-position

The text-underline-position CSS property specifies the position of the underline which is set using the text-decoration property's underline value.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

Syntax

/* Single keyword */
text-underline-position: auto;
text-underline-position: under;
text-underline-position: left;
text-underline-position: right;

/* Multiple keywords */
text-underline-position: under left;
text-underline-position: right under;

/* Global values */
text-underline-position: inherit;
text-underline-position: initial;
text-underline-position: unset;

Syntax

Values

auto

The user agent uses its own algorithm to place the line at or under the alphabetic baseline.

from-font

If the font file includes information about a preferred position, use that value. If the font file doesn't include this information, behave as if auto was set, with the browser choosing an appropriate position.

under

Forces the line to be set below the alphabetic baseline, at a position where it won't cross any descenders. This is useful for ensuring legibility with chemical and mathematical formulas, which make a large use of subscripts.

left

In vertical writing-modes, this keyword forces the line to be placed on the left side of the text. In horizontal writing-modes, it is a synonym of under.

right

In vertical writing-modes, this keyword forces the line to be placed on the right side of the text. In horizontal writing-modes, it is a synonym of under.

auto-pos '

A synonym of auto, which should be used instead.

above '

Forces the line to be above the text. When used with East-Asian text, using the auto keyword will lead to a similar effect.

below '

Forces the line to be below the text. When used with alphabetic text, using the auto keyword will lead to a similar effect.

Formal definition

Initial value	auto
Applies to	all elements
Inherited	yes
Computed value	as specified
Animation type	discrete

Formal syntax

auto | from-font | [ under || [ left | right ] ]

Examples

A simple example

Let's take a couple of simple example paragraphs:

<p class="horizontal">Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Nullam consectetur ac turpis vel laoreet. Nullam volutpat pharetra lorem, sit 
amet feugiat tortor volutpat quis. Nam eget sodales quam. Aliquam accumsan 
tellus ac erat posuere.</p>

<p class="vertical">Lorem ipsum dolor sit amet, consectetur adipiscing elit. 
Nullam consectetur ac turpis vel laoreet. Nullam volutpat pharetra lorem, sit 
amet feugiat tortor volutpat quis. Nam eget sodales quam. Aliquam accumsan 
tellus ac erat posuere.</p>

Our CSS looks like this:

p {
  font-size: 1.5rem;
  text-transform: capitalize;
  text-decoration: underline;
  text-decoration-thickness: 2px;
}

.horizontal {
  text-underline-position: under;
}

.vertical {
  writing-mode: vertical-rl;
  text-underline-position: left;
}

In this example we set both the paragraphs to have a thick underline. In the horizontal text we use text-underline-position: under; to put the underline below all the descenders.

In the text with a vertical writing-mode set, we can then use values of left or right to make the underline appear on the left or right of the text as required.

The live example looks like this:

Setting text-underline-position globally

Because the text-underline-position property inherits and is not reset by the text-decoration shorthand property, it may be appropriate to set its value at a global level. For example, the under value may be appropriate for a document with lots of chemical and mathematical formulas, which make a large use of subscripts.

:root {
  text-underline-position: under;
}

Specifications

Specification	Status	Comment
CSS Text Decoration Module Level 3The definition of 'text-underline-position' in that specification.	Candidate Recommendation	Initial definition

Browser compatibility

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
text-underline-position	Chrome Full support 33	Edge Full support 12	Firefox Full support 74	IE Full support 6	Opera Full support 20	Safari Full support 12.1 Full support 12.1 Full support 9 Prefixed' Prefixed' Implemented with the vendor prefix: -webkit-	WebView Android Full support 4.4.3	Chrome Android Full support 33	Firefox Android No support No	Opera Android Full support 20	Safari iOS No support No	Samsung Internet Android Full support 2.0
above and below Experimental'Non-standard'	Chrome No support No	Edge No support 12 — 79	Firefox Full support 74	IE Full support 6	Opera No support No	Safari No support No	WebView Android No support No	Chrome Android No support No	Firefox Android No support No	Opera Android No support No	Safari iOS No support No	Samsung Internet Android No support No
auto-pos Experimental'Non-standard'	Chrome No support No	Edge No support 12 — 79	Firefox No support No	IE Full support 6	Opera No support No	Safari No support No	WebView Android No support No	Chrome Android No support No	Firefox Android No support No	Opera Android No support No	Safari iOS No support No	Samsung Internet Android No support No
from-font	Chrome No support No	Edge No support No	Firefox Full support 74	IE No support No	Opera No support No	Safari No support No	WebView Android No support No	Chrome Android No support No	Firefox Android No support No	Opera Android No support No	Safari iOS No support No	Samsung Internet Android No support No
left and right	Chrome Full support 71	Edge Full support 79	Firefox Full support 74	IE No support No	Opera Full support 58	Safari No support No	WebView Android Full support 71	Chrome Android Full support 71	Firefox Android No support No	Opera Android Full support 50	Safari iOS No support No	Samsung Internet Android Full support 10.0
under	Chrome Full support 33	Edge Full support 79	Firefox Full support 74	IE No support No	Opera Full support 20	Safari Full support 12.1	WebView Android Full support 4.4.3	Chrome Android Full support 33	Firefox Android No support No	Opera Android Full support 20	Safari iOS No support No	Samsung Internet Android Full support 2.0

Legend

Full support  

Full support

No support  

No support

Experimental. Expect behavior to change in the future.'

Experimental. Expect behavior to change in the future.

Non-standard. Expect poor cross-browser support.'

Non-standard. Expect poor cross-browser support.

Requires a vendor prefix or different name for use.'

Requires a vendor prefix or different name for use.

See also

• The text-decoration property is a shorthand for setting most text-decoration properties, including text-decoration-line, text-decoration-color, and text-decoration-style. However, it does not set text-underline-position.
• Microsoft non-standard values documentation

text-underline-position by Mozilla Contributors is licensed under CC-BY-SA 2.5.