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text-decoration-thickness

The text-decoration-thickness CSS property sets the stroke thickness of the decoration line that is used on text in an element, such as a line-through, underline, or overline.

Syntax

/* Single keyword */
text-decoration-thickness: auto;
text-decoration-thickness: from-font;

/* length */
text-decoration-thickness: 0.1em;
text-decoration-thickness: 3px;

/* percentage */
text-decoration-thickness: 10%;

/* Global values */
text-decoration-thickness: inherit;
text-decoration-thickness: initial;
text-decoration-thickness: unset;

Values

auto
The browser chooses an appropriate width for the text decoration line.
from-font
If the font file includes information about a preferred thickness, use that value. If the font file doesn't include this information, behave as if auto was set, with the browser choosing an appropriate thickness.
<length>
Specifies the thickness of the text decoration line as a <length>, overriding the font file suggestion or the browser default.
<percentage>
Specifies the thickness of the text decoration line as a <percentage> of 1em in the current font. A percentage inherits as a relative value, and so therefore scales with changes in the font. The browser must use a minimum of 1 device pixel. For a given application of this property, the thickness is constant across the whole box it is applied to, even if there are child elements with a different font size.

Formal definition

Initial value auto
Applies to all elements. It also applies to ::first-letter and ::first-line.
Inherited no
Percentages refer to the font size of the element itself
Computed value as specified
Animation type by computed value type

Formal syntax

auto | from-font | <length> | <percentage>

Examples

Varying thickness

HTML

<p class="thin">Here's some text with a 1px red underline.</p>
<p class="thick">This one has a 5px red underline.</p>
<p class="shorthand">This uses the equivalent shorthand.</p>

CSS

.thin { 
  text-decoration-line: underline;
  text-decoration-style: solid;
  text-decoration-color: red;
  text-decoration-thickness: 1px;
}

.thick {
  text-decoration-line: underline;
  text-decoration-style: solid;
  text-decoration-color: red;
  text-decoration-thickness: 5px;
}

.shorthand {
  text-decoration: underline solid red 5px;
}

Results

Specifications

Note: The property used to be called text-decoration-width, but was updated in 2019 to text-decoration-thickness.

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
text-decoration-thickness No No 70
70
69
Disabled
Uses the non-standard name: text-decoration-width
Disabled From version 69: this feature is behind the layout.css.text-decoration-width.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
No No 12.1
percentage values No No 74 No No No
Mobile
Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
text-decoration-thickness No No No No 12.2 No
percentage values No No No No No No

See also

© 2005–2020 Mozilla and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/CSS/text-decoration-thickness