border-image-outset

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since February 2017.

The border-image-outset CSS property sets the distance by which an element's border image is set out from its border box.

The parts of the border image that are rendered outside the element's border box with border-image-outset do not trigger overflow scrollbars and don't capture mouse events.

Try it

Syntax

css
/* <length> value */
border-image-outset: 1rem;

/* <number> value */
border-image-outset: 1.5;

/* top and bottom | left and right */
border-image-outset: 1 1.2;

/* top | left and right | bottom */
border-image-outset: 30px 2 45px;

/* top | right | bottom | left */
border-image-outset: 7px 12px 14px 5px;

/* Global values */
border-image-outset: inherit;
border-image-outset: initial;
border-image-outset: revert;
border-image-outset: revert-layer;
border-image-outset: unset;

The border-image-outset property may be specified as one, two, three, or four values. Each value is a <length> or <number>. Negative values are invalid and will cause the border-image-outset declaration to be ignored.

  1. If one value is specified, it applies to all four sides.
  2. If two values are specified, the first applies to the top and bottom and the second to the left and right.
  3. If three values are specified, the first applies to the top, the second to the left and right, and the third to the bottom.
  4. If four values are specified, they apply to the top, right, bottom, and left in that order (clockwise).

Values

<length>

The size of the border-image outset as a dimension — a number with a unit.

<number>

The size of the border-image outset as a multiple of the element's corresponding border-widths. For example, if an element has border-width: 1em 2px 0 1.5rem, and border-image-outset: 2, the final border-image-outset would be calculated as 2em 4px 0 3rem.

Formal definition

Initial value0
Applies toall elements, except internal table elements when border-collapse is collapse. It also applies to ::first-letter.
Inheritedno
Computed valueas specified, but with relative lengths converted into absolute lengths
Animation typeby computed value type

Formal syntax

border-image-outset = 
[ <length [0,∞]> | <number [0,∞]> ]{1,4}

Examples

Outsetting a border image

HTML

html
<div id="outset">This element has an outset border image!</div>

CSS

css
#outset {
  width: 10rem;
  background: #cef;
  border: 1.4rem solid;
  border-image: radial-gradient(#ff2, #55f) 40;
  border-image-outset: 1.5; /* 1.5 × 1.4rem = 2.1rem */
  margin: 2.1rem;
}

Result

Specifications

Specification
CSS Backgrounds and Borders Module Level 3
# the-border-image-outset

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
border-image-outset

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support

See also