height - CSS: Cascading Style Sheets 编辑

The height CSS property specifies the height of an element. By default, the property defines the height of the content area. If box-sizing is set to border-box, however, it instead determines the height of the border area.

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The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

The min-height and max-height properties override height.

Syntax

/* Keyword value */
height: auto;

/* <length> values */
height: 120px;
height: 10em;

/* <percentage> value */
height: 75%;

/* Global values */
height: inherit;
height: initial;
height: unset;

Values

<length>

Defines the height as an absolute value.

<percentage>

Defines the height as a percentage of the containing block's height.

auto

The browser will calculate and select a height for the specified element.

max-content

The intrinsic preferred height.

min-content

The intrinsic minimum height.

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, )).

Accessibility concerns

Ensure that elements set with a height 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

Formal definition

Initial value	auto
Applies to	all elements but non-replaced inline elements, table columns, and column groups
Inherited	no
Percentages	The percentage is calculated with respect to the height of the generated box's containing block. If the height of the containing block is not specified explicitly (i.e., it depends on content height), and this element is not absolutely positioned, the value computes to auto. A percentage height on the root element is relative to the initial containing block.
Computed value	a percentage or auto or the absolute length
Animation type	a length, percentage or calc();

Formal syntax

auto | <length> | <percentage> | min-content | max-content | fit-content(<length-percentage>)
where 
<length-percentage> = <length> | <percentage>

Examples

Setting height using pixels and percentages

HTML

<div id="taller">I'm 50 pixels tall.</div>
<div id="shorter">I'm 25 pixels tall.</div>
<div id="parent">
  <div id="child">
    I'm half the height of my parent.
  </div>
</div>

CSS

div {
  width: 250px;
  margin-bottom: 5px;
  border: 2px solid blue;
}

#taller {
  height: 50px;
}

#shorter {
  height: 25px;
}

#parent {
  height: 100px;
}

#child {
  height: 50%;
  width: 75%;
}

Result

Specifications

Specification	Status	Comment
CSS Box Sizing Module Level 4 The definition of 'height' in that specification.	Editor's Draft
CSS Box Sizing Module Level 3 The definition of 'height' in that specification.	Working Draft	Added the max-content, min-content, fit-content keywords.
CSS Level 2 (Revision 1) The definition of 'height' in that specification.	Recommendation	Adds support for the <length> values and precises on which element it applies to.
CSS Level 1 The definition of 'height' in that specification.	Recommendation	Initial definition.

Browser compatibility

BCD tables only load in the browser

See also

• The box model, box-sizing
• max-height, min-height
• The mapped logical properties: block-size, inline-size