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The max-height CSS descriptor specifies the maximum height of the viewport of a document defined via the @viewport at-rule.

The height will initially be set as close as possible to the initial viewport height considering the maximum height constraint.

Related at-rule@viewport
Initial valueauto
Percentagesrefer to the height of the initial viewport
Mediavisual, continuous
Computed valueif specified as a length, the corresponding absolute length; if specified as a percentage, the specified value; otherwise, auto
Canonical orderthe unique non-ambiguous order defined by the formal grammar


/* Keyword value */
max-height: auto;

/* <length> values */
max-height: 400px;
max-height: 50em;
max-height: 20cm;

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


The used value is calculated from the other CSS descriptors' values.
A non-negative absolute or relative length.
A percentage value relative to the height of the initial viewport at zoom factor 1.0 for vertical lengths. Must be non-negative.

Formal syntax


<viewport-length> = auto | <length-percentage>

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


@viewport {
  max-height: 600px;


Specification Status Comment
CSS Device Adaptation
The definition of '"max-height" descriptor' in that specification.
Working Draft Initial definition

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support29 ? No10 -ms-


11.1 — 15

FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support4.429 ? No


11.1 — 15

No ?

Document Tags and Contributors

 Contributors to this page: fscholz, mfluehr, Sebastianz, tuttza
 Last updated by: fscholz,