X

Headline

This is an important message requiring you to make a choice if you're based in the EU.

CSS border-top-width Property

The border-top-width property is used to define the width of an element’s top border.

The top border width, as well as all the other border sides, can also be defined with the border or border-width shorthand properties.

For setting the border-top-width you should first define the border-style property, because you need borders before setting its width. You can use either border-top-style or border-style to specify the border's style.

The specification doesn't define the exact thickness of each keyword. However, they always follow this order: thin ≤ medium ≤ thick.

The specification does not define how borders of different width and styles connect in the corners.

Initial Value medium
Applies to All elements. It also applies to ::first-letter.
Inherited No
Animatable Yes. The width of the border is animatable.
Version CSS1
DOM Syntax object.style.borderTopWidth = "5px";

Syntax

border-top-width: medium | thin | thick | length | initial | inherit;

Example of theborder-top-width property:

<!DOCTYPE html>
<html>
  <head>
    <title>Title of the document</title>
    <style>
      p {
      padding: 8px;             
      border-style: dotted;
      border-top-width: thick;
      }
    </style>
  </head>
  <body>
    <h2>Border-top-width example</h2>
    <p>As you can see the width of the top border is set to thick.</p>
  </body>
</html>

Example of the border-top-width property with all values:

<!DOCTYPE html>
<html>
  <head>
    <title>Title of the document</title>
    <style>
      body {
      background: #ccc;
      font-size: 20px;
      text-align: center;
      }
      main div {
      display: flex;
      align-items: center;      
      justify-content: center;
      color: black;
      padding-top: 30px;
      padding-bottom: 30px;
      width: 200px;
      height: 100px;
      margin: 15px;
      font-weight: bold;
      border: solid;
      }
      .flex-center {
      display: flex;
      justify-content: center;
      }
      /* border-top-width example classes */
      .b1 {border-top-width: medium;}
      .b2 {border-top-width: thin;}
      .b3 {border-top-width: thick;}
      .b4 {border-top-width: 10px;}
      .b5 {border-top-width: initial;}
      .b6 {border-top-width: inherit;}
    </style>
  </head>
  <body>
    <h2>Border-top-width value examples</h2>
    <main class="flex-center">
      <div class="b1">
        medium
      </div>
      <div  class="b2">
        thin
      </div>
      <div  class="b3">
        thick
      </div>
    </main>
    <main class="flex-center">
      <div  class="b4">
        10px lenght
      </div>
      <div class="b5">
        initial
      </div>
      <div class="b6">
        inherit
      </div>
    </main>
    </div>
    </main>
  </body>
</html>

Values

Value Descriptions
medium Defines medium top border. It is the default value of this property.
thin Defines a thin top border. It is up to the user agent to determine the exact width.
thick Defines a thick top border. It is up to the user agent to determine the exact width.
length Defines the the thickness length of the top border. For example, 10px, 5em, 8pt, etc.
initial Sets the property to its default value.
inherit Inherits the property from its parent element.


Browser support

1.0+ 12.0+ 1.0+ 1.0+ 3.5+


Do you find this helpful?

Related articles