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.

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

/* <length> values */
width: 300px;
width: 25em;

/* <percentage> 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

<length>: Defines the width as a distance value.
<percentage>: Defines the width as a percentage of the containing block's width.
auto: The browser will calculate and select a width for the specified element.
max-content: The intrinsic preferred width.
min-content: The intrinsic minimum width.
fit-content(<length-percentage>): Uses the fit-content formula with the available space replaced by the specified argument, i.e. min(max-content, max(min-content, <length-percentage>)).

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 except non-replaced inlines
Inherited	no
Computed value	as specified, with <length-percentage> values computed
Animation type	by computed value type, recursing into fit-content()

Formal syntax

auto | <length-percentage [0,∞]> | min-content | max-content | fit-content(<length-percentage [0,∞]>)

Examples

Default width

p.goldie {
  background: gold;
}

<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 px</div>
<div class="em_length">Width measured in em</div>

Example with percentage

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

<div class="percent">Width in percentage</div>

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>

css properties width