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 valueauto
Applies toall elements. It also applies to ::first-letter and ::first-line.
Inheritedno
Percentagesrefer to the font size of the element itself
Computed valueas specified
Animation typeby 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

Specification Status Comment
CSS Text Decoration Module Level 4
The definition of 'text-decoration-width' in that specification.
Working Draft Initial definition.

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

Browser compatibility

BCD tables only load in the browser

See also