`text-decoration-thickness` CSS property

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.

Try it

text-decoration-line: underline;
text-decoration-thickness: 3px;

text-decoration-line: line-through;
text-decoration-thickness: 0.4rem;

text-decoration-line: underline overline;
text-decoration-thickness: from-font;
font-size: 2rem;

<section id="default-example">
  <p id="example-element">
    Confusion kissed me on the cheek, and left a taste so bittersweet
  </p>
</section>

p {
  font: 1.5em sans-serif;
  text-decoration-color: red;
}

Syntax

css

/* 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: revert;
text-decoration-thickness: revert-layer;
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

text-decoration-thickness = 
  auto                 |
  from-font            |
  <length-percentage>  |
  <line-width>         

<length-percentage> = 
  <length>      |
  <percentage>  

<line-width> = 
  <length [0,∞]>  |
  hairline        |
  thin            |
  medium          |
  thick

Examples

undefined

Varying thickness

HTML

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

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

CSS Text Decoration Module Level 4

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

text-decoration-thickness CSS property