CSS border-bottom-width Property

Last Updated : 15 May, 2026

The border-bottom-width property in CSS is used to specify the width (thickness) of the bottom border of an element. It controls how thick or thin the bottom border appears.

  • It accepts values like thin, medium, thick, or specific units such as px, em, etc.
  • The border is visible only when a border style is defined (e.g., solid, dashed).
  • It is commonly used with border-bottom-style and border-bottom-color for complete border styling.

Syntax:

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

Property Values: The border-bottom-width property values are listed below:

ValueDescription
thinSets a thin border width.
mediumSets a medium border width (default).
thickSets a thick border width.
lengthSets the border width using a specific length value. Does not accept negative values.

Example: Here, we demonstrates the border-bottom-width property using different values (thin, medium, thick, and 20px). Each styled <div> shows a solid green bottom border with specified widths, illustrating how each value affects border thickness.

html
<!--Driver Code Starts-->
<!DOCTYPE html>
<html>

<head>
    <title>
        border-bottom-width property
    </title>

<!--Driver Code Ends-->

    <style>
        #thin {
            border-color: green;
            border-bottom-style: solid;
            border-bottom-width: thin;
        }

        #medium {
            border-color: green;
            border-bottom-style: solid;
            border-bottom-width: medium;
        }

        #thick {
            border-color: green;
            border-bottom-style: solid;
            border-bottom-width: thick;
        }

        #length {
            border-color: green;
            border-bottom-style: solid;
            border-bottom-width: 20px;
        }
    </style>

<!--Driver Code Starts-->
</head>

<body style="text-align:center">

    <h1 style="color:green">GeeksforGeeks</h1>

    <h3>border-bottom-width property</h3>

    <div id="thin">
        border-bottom-width: thin;
    </div><br><br>

    <div id="medium">
        border-bottom-width: medium;
    </div><br><br>

    <div id="thick">
        border-bottom-width: thick;
    </div><br><br>

    <div id="length">
        border-bottom-width: length;
    </div>
</body>

</html>

<!--Driver Code Ends-->

 

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