border-inline-start-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 January 2020.

The border-inline-start-width CSS property defines the width of the logical inline-start border of an element, which maps to a physical border width depending on the element's writing mode, directionality, and text orientation. It corresponds to the border-top-width, border-right-width, border-bottom-width, or border-left-width property depending on the values defined for writing-mode, direction, and text-orientation.

Try it

border-inline-start-width: thick;
writing-mode: horizontal-tb;
border-inline-start-width: thick;
writing-mode: vertical-rl;
border-inline-start-width: 4px;
writing-mode: horizontal-tb;
direction: rtl;
<section class="default-example" id="default-example">
  <div class="transition-all" id="example-element">
    This is a box with a border around it.
  </div>
</section>
#example-element {
  background-color: palegreen;
  color: black;
  border: 0 solid crimson;
  padding: 0.75em;
  width: 80%;
  height: 100px;
  unicode-bidi: bidi-override;
}

Syntax

css
/* <'border-width'> values */
border-inline-start-width: 5px;
border-inline-start-width: thick;

/* Global values */
border-inline-start-width: inherit;
border-inline-start-width: initial;
border-inline-start-width: revert;
border-inline-start-width: revert-layer;
border-inline-start-width: unset;

Related properties are border-block-start-width, border-block-end-width, and border-inline-end-width, which define the other border widths of the element.

Values

<'border-width'>

The width of the border. See border-width.

Formal definition

Initial valuemedium
Applies toall elements
Inheritedno
Percentageslogical-width of containing block
Computed valueabsolute length; 0 if the border style is none or hidden
Animation typeby computed value type

Formal syntax

border-inline-start-width = 
<line-width>

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

Examples

HTML

html
<div>
  <p class="exampleText">Example text</p>
</div>

CSS

css
div {
  background-color: yellow;
  width: 120px;
  height: 120px;
}

.exampleText {
  writing-mode: vertical-lr;
  border: 1px solid blue;
  border-inline-start-width: 5px;
}

Specifications

Specification
CSS Logical Properties and Values Module Level 1
# border-width

Browser compatibility

desktop mobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
border-inline-start-width
Chrome – Full support
Chrome 69 (Release date: 2018-09-04)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 41 (Release date: 2015-09-22)
footnote Full support
Opera – Full support
Opera 56 (Release date: 2018-09-25)
footnote Full support
Safari – Full support
Safari 12.1 (Release date: 2019-03-25)
footnote Full support
Chrome Android – Full support
Chrome Android 69 (Release date: 2018-09-04)
footnote Full support
Firefox for Android – Full support
Firefox for Android 41 (Release date: 2015-09-22)
footnote Full support
Opera Android – Full support
Opera Android 48 (Release date: 2018-11-08)
footnote Full support
Safari on iOS – Full support
Safari on iOS 12.2 (Release date: 2019-03-25)
footnote Full support
Samsung Internet – Full support
Samsung Internet 10 (Release date: 2019-08-22)
footnote Full support
WebView Android – Full support
WebView Android 69 (Release date: 2018-09-04)
footnote Full support
WebView on iOS – Full support
WebView on iOS 12.2 (Release date: 2019-03-25)
footnote Full support
medium
Chrome – Full support
Chrome 69 (Release date: 2018-09-04)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 41 (Release date: 2015-09-22)
footnote Full support
Opera – Full support
Opera 56 (Release date: 2018-09-25)
footnote Full support
Safari – Full support
Safari 12.1 (Release date: 2019-03-25)
footnote Full support
Chrome Android – Full support
Chrome Android 69 (Release date: 2018-09-04)
footnote Full support
Firefox for Android – Full support
Firefox for Android 41 (Release date: 2015-09-22)
footnote Full support
Opera Android – Full support
Opera Android 48 (Release date: 2018-11-08)
footnote Full support
Safari on iOS – Full support
Safari on iOS 12.2 (Release date: 2019-03-25)
footnote Full support
Samsung Internet – Full support
Samsung Internet 10 (Release date: 2019-08-22)
footnote Full support
WebView Android – Full support
WebView Android 69 (Release date: 2018-09-04)
footnote Full support
WebView on iOS – Full support
WebView on iOS 12.2 (Release date: 2019-03-25)
footnote Full support
thick
Chrome – Full support
Chrome 69 (Release date: 2018-09-04)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 41 (Release date: 2015-09-22)
footnote Full support
Opera – Full support
Opera 56 (Release date: 2018-09-25)
footnote Full support
Safari – Full support
Safari 12.1 (Release date: 2019-03-25)
footnote Full support
Chrome Android – Full support
Chrome Android 69 (Release date: 2018-09-04)
footnote Full support
Firefox for Android – Full support
Firefox for Android 41 (Release date: 2015-09-22)
footnote Full support
Opera Android – Full support
Opera Android 48 (Release date: 2018-11-08)
footnote Full support
Safari on iOS – Full support
Safari on iOS 12.2 (Release date: 2019-03-25)
footnote Full support
Samsung Internet – Full support
Samsung Internet 10 (Release date: 2019-08-22)
footnote Full support
WebView Android – Full support
WebView Android 69 (Release date: 2018-09-04)
footnote Full support
WebView on iOS – Full support
WebView on iOS 12.2 (Release date: 2019-03-25)
footnote Full support
thin
Chrome – Full support
Chrome 69 (Release date: 2018-09-04)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 41 (Release date: 2015-09-22)
footnote Full support
Opera – Full support
Opera 56 (Release date: 2018-09-25)
footnote Full support
Safari – Full support
Safari 12.1 (Release date: 2019-03-25)
footnote Full support
Chrome Android – Full support
Chrome Android 69 (Release date: 2018-09-04)
footnote Full support
Firefox for Android – Full support
Firefox for Android 41 (Release date: 2015-09-22)
footnote Full support
Opera Android – Full support
Opera Android 48 (Release date: 2018-11-08)
footnote Full support
Safari on iOS – Full support
Safari on iOS 12.2 (Release date: 2019-03-25)
footnote Full support
Samsung Internet – Full support
Samsung Internet 10 (Release date: 2019-08-22)
footnote Full support
WebView Android – Full support
WebView Android 69 (Release date: 2018-09-04)
footnote Full support
WebView on iOS – Full support
WebView on iOS 12.2 (Release date: 2019-03-25)
footnote Full support

Legend

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

Full support
Full support

See also