Css content property width

width

The width CSS property sets an element’s width. By default, it sets the width of the content area, but if box-sizing is set to border-box , it sets the width of the border area.

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The specified value of width applies to the content area so long as its value remains within the values defined by min-width and max-width .

• If the value for width is less than the value for min-width , then min-width overrides width .
• If the value for width is greater than the value for max-width , then max-width overrides width .

Syntax

/* values */ width: 300px; width: 25em; /* value */ width: 75%; /* Keyword values */ width: max-content; width: min-content; width: fit-content(20em); width: auto; /* Global values */ width: inherit; width: initial; width: revert; width: revert-layer; width: unset; 

Values

Defines the width as a distance value.

Defines the width as a percentage of the containing block’s width.

The browser will calculate and select a width for the specified element.

The intrinsic preferred width.

The intrinsic minimum width.

Uses the fit-content formula with the available space replaced by the specified argument, i.e. min(max-content, max(min-content, )) .

Accessibility concerns

Ensure that elements set with a width aren’t truncated and/or don’t obscure other content when the page is zoomed to increase text size.

Formal definition

Initial value	auto
Applies to	all elements but non-replaced inline elements, table rows, and row groups
Inherited	no
Percentages	refer to the width of the containing block
Computed value	a percentage or auto or the absolute length
Animation type	a length, percentage or calc();

Formal syntax

width =
auto |
|
min-content |
max-content |
fit-content( )

=
|

Examples

Default width

p class="goldie">The Mozilla community produces a lot of great software.p> 

Example using pixels and ems

.px_length  width: 200px; background-color: red; color: white; border: 1px solid black; > .em_length  width: 20em; background-color: white; color: red; border: 1px solid black; > 

div class="px_length">Width measured in pxdiv> div class="em_length">Width measured in emdiv> 

Example with percentage

.percent  width: 20%; background-color: silver; border: 1px solid red; > 

div class="percent">Width in percentagediv> 

Example using «max-content»

p.maxgreen  background: lightgreen; width: intrinsic; /* Safari/WebKit uses a non-standard name */ width: -moz-max-content; /* Firefox/Gecko */ width: -webkit-max-content; /* Chrome */ width: max-content; > 

p class="maxgreen">The Mozilla community produces a lot of great software.p> 

Example using «min-content»

p.minblue  background: lightblue; width: -moz-min-content; /* Firefox */ width: -webkit-min-content; /* Chrome */ width: min-content; > 

p class="minblue">The Mozilla community produces a lot of great software.p> 

Specifications

Browser compatibility

BCD tables only load in the browser

See also

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width

The width property in CSS specifies the width of the element’s content area. This “content” area is the portion inside the padding, border, and margin of an element (the box model).

In the example above, elements that have a class name of .wrap will be 80% as wide as their parent element. The accepted values are any of the length values, in addition to some keywords we’ll cover later. Width can be overridden by the closely correleated properties min-width and max-width .

When using percentage (%) for width, authors must be aware that the percentage is based on the element’s parent, or in other words, the width of the containing block. If your parent is set at 480px – as demonstrated by our demo – then the percentage is based on that value. So in our case 50% of 480px leaves us with 240px as a computed pixel value. Note that width applies to all elements except non-replaced or inline elements, table rows and row groups (i.e. thead , tfoot and tbody ). There seems to be a slight mismatch as far as how HTML defines non-replaced elements and how CSS defines it, but we’re referring to it the way CSS does: elements whose content is not defined by the tag itself, such as an with the src attribute. For absolutely positioned elements whose containing block is based on a block container element, the percentage is calculated with respect to the width of the padding box of that element.

With some special keyword values, it is possible to define width (and/or height) according to the content of the element.

The min-content value is the smallest measure that would fit around its content if all soft wrap opportunities within the box were taken. The best example for this kind of value is a properly written figure element:

If we wanted that figure element to essentially be the size of that image, so the text wraps at the edges of the image. We could float it left or right, because float will exhibit that same kind of shrink-to-fit behavior, but what if we wanted to center it? min-content allows us to center it:

Because we’ve assigned min-content to the figure element, it takes the minimum width it can have when taking all soft wrap opportunities (like spaces between words) so that the content still fits in the box.

The max-content property refers to the narrowest measure a box could take while fitting around its content – if no soft wrap opportunities within the element were taken. Check out what happens if we apply this to our simple kitten/figure demo:

Because the caption is very longer than the image is wide (it doesn’t take any soft wrap opportunity, like the spaces between words), it means it has to display the caption on a single line, thus the figure is as wide as that line.

The fit-content value is roughly equivalent to margin-left: auto and margin-right: auto in behaviour, except it works for unknown widths. For instance, let’s say we need to center an inline navigation across the page. Your best bet would be to apply text-align: center to the ul , and display: inline-block to the li . This would give you something like this:

However, the blue background (from the ul element) spreads across the entire document because the ul is a block-level element, which means its width is restricted only by its containing element. What if we want to have the blue background collapsing around the list items? fit-content to the rescue!

With fit-content and margin: 1em auto , this works like a charm and only the navigation has a colored background, not the whole document width. If you’re into this sort of thing, you’ll be happy to know the formula to define the size of a fit-content length is:

fit-content = min(max-content, max(min-content, fill-available))

IE	Edge	Firefox	Chrome	Safari	Opera
All	All	All	All	All	All

Android Chrome	Android Firefox	Android Browser	iOS Safari	Opera Mobile
All	All	All	All	All

Source: caniuse

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box-sizing

The box-sizing CSS property sets how the total width and height of an element is calculated.

Try it

By default in the CSS box model, the width and height you assign to an element is applied only to the element’s content box. If the element has any border or padding, this is then added to the width and height to arrive at the size of the box that’s rendered on the screen. This means that when you set width and height , you have to adjust the value you give to allow for any border or padding that may be added. For example, if you have four boxes with width: 25%; , if any has left or right padding or a left or right border, they will not by default fit on one line within the constraints of the parent container.

The box-sizing property can be used to adjust this behavior:

• content-box gives you the default CSS box-sizing behavior. If you set an element’s width to 100 pixels, then the element’s content box will be 100 pixels wide, and the width of any border or padding will be added to the final rendered width, making the element wider than 100px.
• border-box tells the browser to account for any border and padding in the values you specify for an element’s width and height. If you set an element’s width to 100 pixels, that 100 pixels will include any border or padding you added, and the content box will shrink to absorb that extra width. This typically makes it much easier to size elements. box-sizing: border-box is the default styling that browsers use for the , , and elements, and for elements whose type is radio , checkbox , reset , button , submit , color , or search .

Note: It is often useful to set box-sizing to border-box to lay out elements. This makes dealing with the sizes of elements much easier, and generally eliminates a number of pitfalls you can stumble on while laying out your content. On the other hand, when using position: relative or position: absolute , use of box-sizing: content-box allows the positioning values to be relative to the content, and independent of changes to border and padding sizes, which is sometimes desirable.

Syntax

box-sizing: border-box; box-sizing: content-box; /* Global values */ box-sizing: inherit; box-sizing: initial; box-sizing: revert; box-sizing: revert-layer; box-sizing: unset; 

The box-sizing property is specified as a single keyword chosen from the list of values below.

Values

This is the initial and default value as specified by the CSS standard. The width and height properties include the content, but does not include the padding, border, or margin. For example, .box renders a box that is 370px wide.

Here, the dimensions of the element are calculated as: width = width of the content, and height = height of the content. (Borders and padding are not included in the calculation.)

The width and height properties include the content, padding, and border, but do not include the margin. Note that padding and border will be inside of the box. For example, .box renders a box that is 350px wide, with the area for content being 330px wide. The content box can’t be negative and is floored to 0, making it impossible to use border-box to make the element disappear.

Here the dimensions of the element are calculated as: width = border + padding + width of the content, and height = border + padding + height of the content.

Formal definition

Formal syntax

Examples

Box sizes with content-box and border-box

This example shows how different box-sizing values alter the rendered size of two otherwise identical elements.

HTML

div class="content-box">Content boxdiv> br /> div class="border-box">Border boxdiv> 

CSS

div  width: 160px; height: 80px; padding: 20px; border: 8px solid red; background: yellow; > .content-box  box-sizing: content-box; /* Total width: 160px + (2 * 20px) + (2 * 8px) = 216px Total height: 80px + (2 * 20px) + (2 * 8px) = 136px Content box width: 160px Content box height: 80px */ > .border-box  box-sizing: border-box; /* Total width: 160px Total height: 80px Content box width: 160px - (2 * 20px) - (2 * 8px) = 104px Content box height: 80px - (2 * 20px) - (2 * 8px) = 24px */ > 

Result

Specifications

Browser compatibility

BCD tables only load in the browser

See also

Found a content problem with this page?

This page was last modified on Jul 18, 2023 by MDN contributors.

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MDN

Support

Our communities

Developers

Visit Mozilla Corporation’s not-for-profit parent, the Mozilla Foundation.
Portions of this content are ©1998– 2023 by individual mozilla.org contributors. Content available under a Creative Commons license.

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