CSS

box-sizing

Property

Example

Include padding and border in
the
element’s total width and height:

#example1 {
  box-sizing: border-box;
}

Try it Yourself »

More “Try it Yourself” examples below.

Definition and Usage

The box-sizing property defines how the width and height of an element are
calculated: should they include padding and borders, or not.

Show demo ❯

Default value:
content-box

Inherited:
no

Animatable:
no. Read about animatable

Version:
CSS3

JavaScript syntax:
object.style.boxSizing=”border-box”
Try it

Browser Support

The numbers in the table specify the first browser version that fully supports the property.

Numbers followed by -webkit- or -moz- specify the first version that worked with a prefix.

Property

box-sizing
10.0
4.0 -webkit-
8.0
29.0
2.0 -moz-
5.1
3.2 -webkit-
9.5

CSS Syntax

box-sizing: content-box|border-box|initial|inherit;

Property Values

Value
Description
Demo

content-box
Default. The width and height properties (and min/max properties) includes only the content. Border
and padding are not included
Demo ❯

border-box
The width and height properties (and min/max properties) includes
content, padding and border
Demo ❯

initial
Sets this property to its default value. Read about initial

inherit
Inherits this property from its parent element. Read about inherit

More Examples

Example

Specify two bordered boxes side by side:

div
{
  box-sizing: border-box;
  width: 50%;
  border: 5px solid red;
 
float: left;
}

Try it Yourself »

Example

Set the “universal box-sizing”:

* {
  box-sizing: border-box;
}

Try it Yourself »

Related Pages

CSS tutorial: CSS Box Sizing

HTML DOM reference: boxSizing property