Test if the current browser runs on a mobile device (smart phone, tablet, etc.)



More Information

This Conditional Tag checks if the user is visiting using a mobile device. This is a boolean function, meaning it returns either TRUE or FALSE. It works through the detection of the browser user agent string ($_SERVER[‘HTTP_USER_AGENT’])

Do not think of this function as a way of detecting phones. Its purpose is not detecting screen width, but rather adjusting for the potentially limited resources of mobile devices. A mobile device may have less CPU power, memory and/or bandwidth available. This function will return true for a tablet, as it too is considered a mobile device. It is not a substitute for CSS media queries or styling per platform.

One way that this function could be used in a theme is to produce a very light version of the site that does not have the large payload of the desktop site. Note that both the desktop and the mobile versions of the page will still need to be responsive, as an older portrait phone will have a significantly different width than a modern iPad in landscape. wp_is_mobile() will be true for both. Similarly a desktop browser window may not be displayed at full width. Essentially this approach may double the amount of work you will need to put into the theme. Yet for a tightly optimized theme or a unique mobile experience, it may be essential. It also means that a proper theme may have at least three different responsive design specs: Desktop, Mobile and AMP.

Additionally, care must be taken when using this function in a public theme. If your theme works differently for mobile devices and desktop devices, any page caching solution used MUST keep separate mobile/non-mobile buckets. Many caching solutions do not do this or charge for this feature. Even the most detailed read me file may not be able to adequately explain these details


File: wp-includes/vars.php

function wp_is_mobile() {
	if ( empty( $_SERVER['HTTP_USER_AGENT'] ) ) {
		$is_mobile = false;
	} elseif ( strpos( $_SERVER['HTTP_USER_AGENT'], 'Mobile' ) !== false // Many mobile devices (all iPhone, iPad, etc.)
		|| strpos( $_SERVER['HTTP_USER_AGENT'], 'Android' ) !== false
		|| strpos( $_SERVER['HTTP_USER_AGENT'], 'Silk/' ) !== false
		|| strpos( $_SERVER['HTTP_USER_AGENT'], 'Kindle' ) !== false
		|| strpos( $_SERVER['HTTP_USER_AGENT'], 'BlackBerry' ) !== false
		|| strpos( $_SERVER['HTTP_USER_AGENT'], 'Opera Mini' ) !== false
		|| strpos( $_SERVER['HTTP_USER_AGENT'], 'Opera Mobi' ) !== false ) {
			$is_mobile = true;
	} else {
		$is_mobile = false;

	 * Filters whether the request should be treated as coming from a mobile device or not.
	 * @since 4.9.0
	 * @param bool $is_mobile Whether the request is from a mobile device or not.
	return apply_filters( 'wp_is_mobile', $is_mobile );


Version Description
3.4.0 Introduced.

© 2003–2019 WordPress Foundation
Licensed under the GNU GPLv2+ License.