CSS3 box-sizing Property


Specify that <div> elements should have padding and border included in the element's total width and height:

.div {
    width: 300px;
    height: 100px;
    border: 1px solid blue;
    box-sizing: border-box;

Try it yourself »

More "Try it Yourself" examples below.

Definition and Usage

The box-sizing property is used to tell the browser what the sizing properties (width and height) should include.

Should they include the border-box? Or just the content-box (which is the default value of the width and height properties)?

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.

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

CSS Syntax

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

Property Values

Value Description
content-box Default. The width and height properties (and min/max properties) includes only the content. Border, padding, or margin are not included
border-box The width and height properties (and min/max properties) includes content, padding and border, but not the margin
initial Sets this property to its default value. Read about initial
inherit Inherits this property from its parent element. Read about inherit


More Examples


Specify two bordered boxes side by side:

div {
    box-sizing: border-box;
    width: 50%;
    float: left;

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Related Pages

CSS3 tutorial: CSS3 Box Sizing

HTML DOM reference: boxSizing property




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