outline-width CSS property
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
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.
Try it
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
css
/* 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;
The outline-width property is specified as any one of the values listed below.
Values
<length>-
The width of the outline specified as a
<length>. thin-
Depends on the user agent. Typically equivalent to
1pxin desktop browsers (including Firefox). medium-
Depends on the user agent. Typically equivalent to
3pxin desktop browsers (including Firefox). thick-
Depends on the user agent. Typically equivalent to
5pxin desktop browsers (including Firefox).
Formal definition
| Initial value | medium |
|---|---|
| Applies to | all elements |
| Inherited | no |
| Computed value | an absolute length; if the keyword none is specified, the computed value is 0 |
| Animation type | a length |
Formal syntax
outline-width =
<line-width>
<line-width> =
<length [0,∞]> |
hairline |
thin |
medium |
thick
Examples
Setting an element's outline width
HTML
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
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
Specifications
| Specification |
|---|
| CSS Basic User Interface Module Level 4 # outline-width |
Browser compatibility
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thin
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Legend
Tip: you can click/tap on a cell for more information.
- Full support
- Full support
- See implementation notes.
- Requires a vendor prefix or different name for use.
- Has more compatibility info.