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.

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

Syntax

/* <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;

Values

<length>

The maximum width as an absolute value.

<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;
}

Accessibility concerns

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.

• MDN Understanding WCAG, Guideline 1.4 explanations
• Understanding Success Criterion 1.4.4 | W3C Understanding WCAG 2.0

Specifications

Browser compatibility

See also

• The box model, box-sizing
• width, min-width