Should I use max-device-width or max-width?

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TL;DR

If you’re making a responsive website, use min-width/max-width in your media queries rather than min-device-width/max-device-width in order to target a wider range of screen sizes.

According to the 2018 Media Queries Level 4 specification draft, the device-width media feature is deprecated. It will be kept for backward compatibility, but should be avoided.

8. Appendix A: Deprecated Media Features

To query for the size of the viewport (or the page box on page media), the width, height and aspect-ratio media features should be used, rather than device-width, device-height and device-aspect-ratio, which refer to the physical size of the the device regardless of how much space is available for the document being laid out. The device-* media features are also sometimes used as a proxy to detect mobile devices. Instead, authors should use media features that better represent the aspect of the device that they are attempting to style against.

As a side note, remember to specify a viewport meta tag in the <head> section of your document:

<meta name="viewport" content="width=device-width, initial-scale=1">

Explanation

Due to all the different possible screen resolutions and pixel densities a given device can have, a pixel is not a pixel because there are several things to take into consideration (zoom, pixel density, screen resolution and size, device orientation, aspect ratio, etc..). In this case, a pixel is actually referred to as a “optical reference unit” rather than a physic hardware pixel.

Fortunately, you can specify a viewport meta tag in the <head> section of your document in order to control the width and scaling of the browser’s viewport. If this tag has a content value of width=device-width, the screen’s width will match the device independent pixels and will ensure that all the different devices should scale and behave consistently.

<meta name="viewport" content="width=device-width, initial-scale=1">

In terms of media queries, you will probably want to use max-width rather than max-device-width, since max-width will target the viewport (current browser window), whereas max-device-width will target the device’s actual full screen size/resolution.

In other words, if you are using max-device-width, you will not see different media queries applied when resizing your desktop browser, because unlike max-width, only the device’s actual full screen size is taken into consideration; not the current size of the browser window.

This makes a huge difference if you’re trying to create an adaptive layout because the site won’t be responsive when resizing the browser. In addition, if you’re using max-device-width the media queries you’re using to target devices with smaller screens will not apply to desktops even when resizing the browser window down to match said smaller screen size.

As of 2018, the latest media query specification draft has actually deprecated the device-width media feature, therefore it should be avoided.

In addition, this article on Google Developers highly discourages the usage of max-device-width:

Google Developers – Web Fundamentals – Responsive CSS media queries

It is also possible to create queries based on *-device-width; though this practice is strongly discouraged.

The difference is subtle but very important: min-width is based on the size of the browser window, whereas min-device-width is based on the size of the screen. Unfortunately some browsers, including the legacy Android browser may not report the device width properly and instead report the screen size in device pixels instead of the expected viewport width.

In addition, using *-device-width can prevent content from adapting on desktops or other devices that allow windows to be resized because the query is based on the actual device size, not the size of the browser window.

Further Reading:

  • Quirksmode.org – A pixel is not a pixel is not a pixel
  • W3 – Media Queries Level 4 Specification
  • Google Developers – Web Fundamentals – Viewport
  • Google Developers – Web Fundamentals – Responsive CSS media queries
  • MDN – Using the viewport meta tag to control layout on mobile browsers

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