CSS box-sizing Property Last Updated : 11 Jul, 2025 Comments Improve Suggest changes Like Article Like Report The CSS box-sizing property controls how an element's size is calculated. When using the border-box model, the padding and border are included in the element’s total width and height, making it easier to manage the layout.Syntaxbox-sizing: content-box | border-box;Property ValuesHere is a description of the property values for the box-sizing property:Property ValueDescriptioncontent-boxThe element’s width and height are calculated excluding padding and borders. Padding and borders are added outside the specified width and height.border-boxThe element’s width and height include padding and borders within the specified dimensions. This makes layout calculations simpler and more predictable.Here are the definitions and syntax for both property values:content-boxThe content-box value for box-sizing calculates an element's width and height, excluding padding and borders, which are added to the specified dimensions.Syntax:box-sizing: content-box;Example: This example illustrates the use of the box-sizing property whose value is set to content-box. HTML <!DOCTYPE html> <html> <head> <title>box-sizing Property</title> <style> div { width: 200px; height: 60px; padding: 20px; border: 2px solid green; background: green; color: white; } .content-box { box-sizing: content-box; } </style> </head> <body style="text-align: center;"> <h2>box-sizing: content-box</h2> <br> <div class="content-box">GeeksforGeeks</div> </body> </html> Output:border-boxThe border-box value for box-sizing calculates an element's width and height, including padding and borders within the specified dimensions, making layout design more straightforward and predictable.Syntax:box-sizing: border-box;Example: This example illustrates the use of the box-sizing property whose value is set to border-box. HTML <!DOCTYPE html> <html> <head> <title>box-sizing Property</title> <style> div { width: 200px; height: 60px; padding: 20px; border: 2px solid green; background: green; color: white; } .border-box { box-sizing: border-box; } </style> </head> <body style="text-align: center;"> <h2>box-sizing: border-box</h2> <br> <div class="border-box">GeeksforGeeks</div> </body> </html> Output:Supported Browsers The browser supported by the box-sizing property are listed below: Google ChromeEdge FirefoxOperaSafariNote: The box-sizing property is widely supported across all modern browsers. It can be safely used in most web projects, ensuring compatibility across different platforms and devices without the need for special fallbacks. Comment More infoAdvertise with us Next Article CSS Introduction V Vishal Chaudhary 2 Follow Improve Article Tags : Web Technologies CSS CSS-Properties Similar Reads CSS Tutorial CSS stands for Cascading Style Sheets. 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