max-width

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

By default, the width is set as close as possible to the initial viewport considering the maximum width constraint.

Syntax

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

/* <length> values */
max-width: 600px;
max-width: 80em;
max-width: 15cm;

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

Values

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

Formal definition

Related at-rule@viewport
Initial valueauto
Percentagesrefer to the width of the initial viewport
Computed valueif specified as a length, the corresponding absolute length; if specified as a percentage, the specified value; otherwise, auto

Formal syntax

<viewport-length>

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

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

Examples

Setting viewport max width in pixels

@viewport {
  max-width: 600px;
}

Specifications

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

Browser compatibility

DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
max-width descriptorChrome No support 29 — 84Edge Full support 12
Prefixed
Full support 12
Prefixed
Prefixed Implemented with the vendor prefix: -ms-
Firefox No support NoIE Full support 10
Prefixed
Full support 10
Prefixed
Prefixed Implemented with the vendor prefix: -ms-
Opera Full support 16
Full support 16
No support 11.1 — 15
Safari No support NoWebView Android No support 4.4 — 37Chrome Android No support 29 — 84Firefox Android No support NoOpera Android Full support 16
Full support 16
No support 11.1 — 14
Safari iOS No support NoSamsung Internet Android Full support 2.0

Legend

Full support
Full support
No support
No support
Requires a vendor prefix or different name for use.
Requires a vendor prefix or different name for use.

See also