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CSS Properties

align-content align-items align-self all animation animation-delay animation-direction animation-duration animation-fill-mode animation-iteration-count animation-name animation-play-state animation-timing-function backface-visibility background background-attachment background-blend-mode background-clip background-color background-image background-origin background-position background-repeat background-size border border-bottom border-bottom-color border-bottom-left-radius border-bottom-right-radius border-bottom-style border-bottom-width border-collapse border-color border-image border-image-outset border-image-repeat border-image-slice border-image-source border-image-width border-left border-left-color border-left-style border-left-width border-radius border-right border-right-color border-right-style border-right-width border-spacing border-style border-top border-top-color border-top-left-radius border-top-right-radius border-top-style border-top-width border-width bottom box-shadow box-sizing caption-side clear clip color column-count column-fill column-gap column-rule column-rule-color column-rule-style column-rule-width column-span column-width columns content counter-increment counter-reset cursor direction display empty-cells filter flex flex-basis flex-direction flex-flow flex-grow flex-shrink flex-wrap float font @font-face font-family font-size font-size-adjust font-stretch font-style font-variant font-weight hanging-punctuation height justify-content @keyframes left letter-spacing line-height list-style list-style-image list-style-position list-style-type margin margin-bottom margin-left margin-right margin-top max-height max-width @media min-height min-width nav-down nav-index nav-left nav-right nav-up opacity order outline outline-color outline-offset outline-style outline-width overflow overflow-x overflow-y padding padding-bottom padding-left padding-right padding-top page-break-after page-break-before page-break-inside perspective perspective-origin position quotes resize right tab-size table-layout text-align text-align-last text-decoration text-decoration-color text-decoration-line text-decoration-style text-indent text-justify text-overflow text-shadow text-transform top transform transform-origin transform-style transition transition-delay transition-duration transition-property transition-timing-function unicode-bidi vertical-align visibility white-space width word-break word-spacing word-wrap z-index


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:"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;
Try it Yourself »

Related Pages

CSS3 tutorial: CSS3 Box Sizing

HTML DOM reference: boxSizing property