css property

`max-width` CSS property

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.

Interactive exampleOpen the canonical MDN source to run this embedded demo.

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

/* <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

Formal syntax

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

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

CSS

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

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

Result