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css property

`outline-width` CSS property

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The CSS outline-width property sets the thickness of an element’s outline. An outline is a line that is drawn around an element, outside the border.

Interactive exampleOpen the canonical MDN source to run this embedded demo.
outline-width: 12px;

outline-width: thin;

outline-width: medium;

outline-width: thick;

<section class="default-example" id="default-example">
  <div class="transition-all" id="example-element">
    This is a box with an outline around it.
  </div>
</section>

#example-element {
  outline: 0.75em solid;
  padding: 0.75em;
  width: 80%;
  height: 100px;
}

It is often more convenient to use the shorthand property outline when defining the appearance of an outline.

Syntax

/* Keyword values */
outline-width: thin;
outline-width: medium;
outline-width: thick;

/* <length> values */
outline-width: 1px;
outline-width: 0.1em;

/* Global values */
outline-width: inherit;
outline-width: initial;
outline-width: revert;
outline-width: revert-layer;
outline-width: unset;

Values

This property is specified as one <line-width> value.

  • &lt;line-width&gt;
    • : Defines the width of the outline, either as an explicit non-negative &lt;length&gt; or the keywords: thin, medium, or thick. The default is medium.

Formal definition

Formal syntax

Examples

Setting an element’s outline width

HTML

<span id="thin">thin</span>
<span id="medium">medium</span>
<span id="thick">thick</span>
<span id="twopixels">2px</span>
<span id="oneex">1ex</span>
<span id="em">1.2em</span>

CSS

span {
  outline-style: solid;
  display: inline-block;
  margin: 20px;
}

#thin {
  outline-width: thin;
}

#medium {
  outline-width: medium;
}

#thick {
  outline-width: thick;
}

#twopixels {
  outline-width: 2px;
}

#oneex {
  outline-width: 1ex;
}

#em {
  outline-width: 1.2em;
}

Result

Interactive exampleOpen the canonical MDN source to run this embedded demo.

Specifications

SpecificationsStandards references are available on the canonical MDN page.

Browser compatibility

Browser compatibilityCompatibility data is available on the canonical MDN page.

See also