max-width

Baseline Widely available *

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨July 2015⁩.

* Some parts of this feature may have varying levels of support.

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.

Try it

max-width: 150px;

max-width: 20em;

max-width: 75%;

max-width: 20ch;

<section class="default-example" id="default-example">
  <div class="transition-all" id="example-element">
    Change the maximum width.
  </div>
</section>

#example-element {
  display: flex;
  flex-direction: column;
  background-color: #5b6dcd;
  height: 80%;
  justify-content: center;
  color: white;
}

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

Syntax

css

/* <length> value */
max-width: 3.5em;
max-width: anchor-size(--my-anchor inline, 245px);
max-width: calc(anchor-size(width) + 4em);

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

/* Keyword values */
max-width: none;
max-width: max-content;
max-width: min-content;
max-width: fit-content;
max-width: fit-content(20em);
max-width: stretch;

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

Values

<length>: Defines the max-width as an absolute value.
<percentage>: Defines the max-width as a percentage of the containing block's width.
none: No limit on the size of the box.
max-content: The intrinsic preferred max-width.
min-content: The intrinsic minimum max-width.
fit-content: Use the available space, but not more than max-content, i.e., min(max-content, max(min-content, stretch)).
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, argument)).
stretch: Limits the maximum width of the element's margin box to the width of its containing block. It attempts to make the margin box fill the available space in the containing block, so in a way behaving similar to 100% but applying the resulting size to the margin box rather than the box determined by box-sizing.

Note: To check aliases used by browsers for the stretch value and its implementation status, see the Browser compatibility section.

Accessibility

Ensure that elements set with a max-width are not truncated and/or do not obscure other content when the page is zoomed to increase text size.

Formal definition

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
Computed value	the percentage as specified or the absolute length or `none`
Animation type	a length, percentage or calc();

Formal syntax

max-width = 
  none                                      |
  <length-percentage [0,∞]>                 |
  min-content                               |
  max-content                               |
  fit-content( <length-percentage [0,∞]> )  |
  <calc-size()>                             |
  <anchor-size()>                           |
  stretch                                   |
  fit-content                               |
  contain                                   

<length-percentage> = 
  <length>      |
  <percentage>  

<calc-size()> = 
  calc-size( <calc-size-basis> , <calc-sum> )  

<anchor-size()> = 
  anchor-size( [ <anchor-name> || <anchor-size> ]? , <length-percentage>? )  

<calc-size-basis> = 
  <size-keyword>  |
  <calc-size()>   |
  any             |
  <calc-sum>      

<calc-sum> = 
  <calc-product> [ [ '+' | '-' ] <calc-product> ]*  

<anchor-name> = 
  <dashed-ident>  

<anchor-size> = 
  width        |
  height       |
  block        |
  inline       |
  self-block   |
  self-inline  

<calc-product> = 
  <calc-value> [ [ '*' | / ] <calc-value> ]*  

<calc-value> = 
  <number>        |
  <dimension>     |
  <percentage>    |
  <calc-keyword>  |
  ( <calc-sum> )  

<calc-keyword> = 
  e          |
  pi         |
  infinity   |
  -infinity  |
  NaN

Examples

Setting max width in pixels

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

HTML

html

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

CSS

css

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

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

Result

Specifications

Specification
CSS Box Sizing Module Level 4 # sizing-values

Browser compatibility

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This page was last modified on ⁨Aug 14, 2025⁩ by MDN contributors.

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