W3cubDocs

/CSS

max-width

The max-width CSS property sets the maximum width of an element. It prevents the used value of the width property from becoming larger than the value specified by max-width.

/* <length> value */
max-width: 3.5em;

/* <percentage> value */
max-width: 75%;

/* Keyword values */
max-width: none;
max-width: max-content;
max-width: min-content;
max-width: fit-content;
max-width: fill-available;

/* Global values */
max-width: inherit;
max-width: initial;
max-width: unset;

max-width overrides width, but min-width overrides max-width.

Initial value	`none`
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
Media	visual
Computed value	the percentage as specified or the absolute length or `none`
Animation type	a length, percentage or calc();
Canonical order	the unique non-ambiguous order defined by the formal grammar

Syntax

Values

<length>: The maximum width, expressed as a <length>.
<percentage>: The maximum width, expressed as a <percentage> of the containing block's width.

Keyword values

none: The width has no maximum value.
max-content: The intrinsic preferred width.
min-content: The intrinsic minimum width.
fill-available: The containing block's width minus the horizontal margin, border, and padding. (Note that some browsers implement an ancient name for this keyword, available.)
fit-content: The same as max-content.

Formal syntax

<length> | <percentage> | none | max-content | min-content | fit-content | fill-available

Examples

In this example, the "child" will be either 150 pixels wide or the width of the "parent," whichever is smaller:

<div id="parent">
  <div id="child">
    Fusce pulvinar vestibulum eros, sed luctus ex lobortis quis.
  </div>
</div>

#parent {
  background: lightblue;
  width: 300px;
}

#child {
  background: gold;
  width: 100%;
  max-width: 150px;
}

The fit-content value can be used to set the width of an element based on the intrinsic size required by its content:

<div id="parent">
    <div id="child">
        Child Text
    </div>
</div>

#parent {
  background: lightblue;
  width: 300px;
}

#child  {
  background: gold;
  width: 100%;
  max-width: -moz-fit-content;
  max-width: -webkit-fit-content;
}

Specifications

Specification	Status	Comment
CSS Intrinsic & Extrinsic Sizing Module Level 3 The definition of 'max-width' in that specification.	Working Draft	Adds the `max-content`, `min-content`, `fit-content`, and `fill-available` keywords.(Both CSS3 Box and CSS3 Writing Modes drafts used to define these keywords, but are superseded by this spec.)
CSS Transitions The definition of 'max-width' in that specification.	Working Draft	Defines `max-width` as animatable.
CSS Level 2 (Revision 1) The definition of 'max-width' in that specification.	Recommendation	Initial definition.

Browser compatibility

Feature	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari
Basic support	1	Yes	1¹	7	4²	2
`fit-content`, `max-content`, and `min-content`	No³	No	3 -moz- ⁴	No	No	No⁵
`fill-available`	No	No	No	No	No	No

Feature	Android webview	Chrome for Android	Edge mobile	Firefox for Android	Opera Android	iOS Safari	Samsung Internet
Basic support	?	?	Yes	?	?	?	?
`fit-content`, `max-content`, and `min-content`	?	?	?	No	?	?	?
`fill-available`	?	?	?	?	?	?	?

1. CSS 2.1 leaves the behavior of max-width with table undefined. Firefox supports applying max-width to table elements.

2. CSS 2.1 leaves the behavior of max-width with table undefined. Opera supports applying max-width to table elements.

3. Chrome implements an earlier proposal for setting width to an intrinsic width: the keywords intrinsic (instead of max-content), and min-intrinsic (instead of min-content). There is no equivalent for fill-available or fit-content.

4. Firefox implements the definitions given in CSS3 Basic Box. This defines available and not fit-available. Also, the definition of fit-content is simpler than in CSS3 Sizing.

5. Safari implements an earlier proposal for setting width to an intrinsic width: the keywords intrinsic (instead of max-content), and min-intrinsic (instead of min-content). There is no equivalent for fill-available or fit-content.