border-top-width

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 border-top-width CSS property sets the width of the top border of an element.

Try it

Syntax

Values

<line-width>

Defines the width of the border, either as an explicit nonnegative <length> or a keyword. If it's a keyword, it must be one of the following values:

  • thin
  • medium
  • thick

Note: Because the specification doesn't define the exact thickness denoted by each keyword, the precise result when using one of them is implementation-specific. Nevertheless, they always follow the pattern thin ≤ medium ≤ thick, and the values are constant within a single document.

Formal definition

Initial valuemedium
Applies toall elements. It also applies to ::first-letter.
Inheritedno
Computed valuethe absolute length or 0 if border-top-style is none or hidden
Animation typea length

Formal syntax

border-top-width = 
<line-width>

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

Examples

HTML

CSS

Result

Specifications

Specification
CSS Backgrounds and Borders Module Level 3
# border-width

Browser compatibility

See also