CSS border-left-width Property


The border-left-width CSS property is used to specify the width of the left border of an element. Borders are commonly applied to elements to create visual distinctions, and this property allows you to control the thickness of the left border independently of the other three borders (top, right, and bottom) using a specified measurement unit, such as pixels, ems, or percentages. By adjusting the "border-left-width," you can achieve various design effects, from creating thin lines to thick dividers, helping to define the layout and appearance of web page elements.

Initial value
Applies to
All elements
Computed value
Absolute length; '0' if the border style is 'none' or 'hidden'
JavaScript syntax

Interactive Demo

The rusty swing set creaked a lonely lullaby in the twilight, shadows lengthening like grasping fingers across the dew-kissed grass. A lone dandelion seed, adrift on the breeze, whispered secrets of faraway fields, of dandelion suns and galaxies spun from fluff. Somewhere, beyond the veil of dusk, a coyote laughed, echoing through the stillness like a forgotten memory.


border-left-width: <line-width> 


<line-width> = <length> | thin | medium | thick
  • thinLess than the default width.
  • mediumDefault value.
  • thickGreater than the default width.
  • <length>Floating-point number, followed by an absolute units designator (cm, mm, in, pt, or pc) or a relative units designator (em, ex, or px).
  • inherit


<div class="border">This is an example of the border-left-width property using a red solid border 3px in width.</div>
.border {
   border: 1px solid blue;
   border-left-style: solid;
   border-left-width: 3px;
   border-left-color: red;
   margin: 20px;
   padding: 20px;

Browser Support

The following table will show you the current browser support for the CSS border-left-width property.

Edge Chrome Firefox Opera Safari
Tablets / Mobile
Chrome Firefox Opera Safari Samsung Webview

Last updated by CSSPortal on: 31st December 2023