How to make a div fill a remaining horizontal space using CSS?

Last Updated : 04 Dec, 2023

The width property is used to fill a div’s remaining horizontal space using CSS. By setting the width to 100% it takes the whole width available of its parent.

Syntax:

width: 100%;

Example 1: This example uses the width property to fill the horizontal space. It set the width to 100% to fill it completely.

html

<!DOCTYPE html>
<html>
 
<head>
    <title>
        make a div fill remaining
        horizontal space
    </title>
 
    <!-- Style to fill remaining 
        horizontal space -->
    <style>
        #main {
            height: 100px;
            border: 1px solid black;
            font-size: 20px;
            font-weight: bold;
            color: white;
        }
 
        #left {
            float: left;
            width: 180px;
            height: 100%;
            background-color: green;
        }
 
        #right {
            width: 100%;
            height: 100%;
            background-color: blue;
        }
    </style>
</head>
 
<body style="text-align:center;">
    <div id="main">
        <div id="left">
            DIV_1
        </div>
 
        <div id="right">
            DIV_2
        </div>
    </div>
</body>
 
</html>

Output:

Example 2: This example uses the width property to fill the horizontal space. It set the width to 100% to fill it completely.

html

<!DOCTYPE html>
<html>
 
<head>
    <style>
        #main {
            height: 100px;
            border: 1px solid black;
            font-size: 20px;
            font-weight: bold;
            color: white;
        }
 
        #left {
            float: left;
            width: 100px;
            height: 100%;
            background-color: green;
        }
 
        #center {
            float: left;
            width: 100px;
            height: 100%;
            background-color: blue;
        }
 
        #right {
            width: 100%;
            height: 100%;
            background-color: green;
        }
    </style>
</head>
 
<body style="text-align:center;">
    <div id="main">
        <div id="left">
            DIV_1
        </div>
 
        <div id="center">
            DIV_2
        </div>
 
        <div id="right">
            DIV_3
        </div>
    </div>
</body>
 
</html>

Output:

CSS is the foundation of webpages, is used for webpage development by styling websites and web apps.You can learn CSS from the ground up by following this CSS Tutorial and CSS Examples.