Border-Width

Shorthand to set the top, right, bottom and left border properties in px, pt, %, em, etc.

element { border-width: TopWidth RightWidth BottomWidth LeftWidth ;}

element { border-width: TopWidth  Right&LeftWidth  BottomWidth ;}

element { border-width: Top&BottomWidth  Right&LeftWidth ;}

element { border-width: Width ;}

Alternatively you can choose to inherit from a parent element: border-width: inherit ;

This shorthand is equivalent to the following:

element {
  border-top-width: thin | medium | thick | length | inherit ;
  border-right-width: thin | medium | thick | length | inherit ;
  border-bottom-width: thin | medium | thick | length | inherit ;
  border-left-width:thin | medium | thick | length | inherit ;
}

The default border width is medium. For dashed borders the border-width will change the size of each dash.

Examples

Set the border widths to 3px and 8px:

h1 {border-width: 3px 8px;}

Try it:

(CSS 1) Browser Support: All major browsers.

“I've learned that our background and circumstances may have influenced who we are, but we are responsible for who we become” ~ James Rhinehart

Related:

border-width - MDN Web Docs.
border-style - Style of the four borders.
border-color - Color of the four borders.
border - Shorthand to set all border properties.
outline-width - Width of an outline.
The CSS Box Model