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Test Responsive and Device-specific Viewports

The updated Device Mode (since Chrome 49) is an integral part of the now-mobile-first DevTools and extends the main DevTools bar. Learn how to use its controls to simulate a wide range of devices or go fully responsive.


  • Test your site's responsiveness using the Device Mode's screen emulator.
  • Save custom presets so you can easily access them later.
  • Device mode isn't a replacement for real device testing. Be aware of its limitations.

Using the viewport controls

device mode enabled

The Viewport Controls allow you to test your site against a variety of devices, as well as fully responsively. It comes in two modes:

  1. Responsive. Makes the Viewport freely resizable via big handles on either side.
  2. Specific Device. Locks the Viewport to the exact viewport size of a specific device and emulates certain device characteristics.

Responsive mode

We recommend using the Responsive Mode as your default work mode. Use it during active development of your site and app and resize the viewport often to create a freely responsive design that adapts to even unknown and future device types.

To get the most out of the Responsive Mode, turn on the Media Queries Bar.

Customize the viewport size

Either drag the big resize handles on the viewport or click into the values in the menu bar for finer grained control.

Device-specific mode

Use the Device-specific Mode when you're nearing the end of active development and want to perfect how your site looks like on specific mobiles (e.g. a certain iPhone or Nexus).

Built-in device presets

We've included the currently most popular devices in the device dropdown. After selecting a device, each preset automatically configures emulation of certain device characteristics:

  • Sets the correct "User Agent" (UA) string.
  • Sets the device resolution and DPI (device pixel ratio).
  • Emulates touch events (if applicable).
  • Emulates mobile scrollbar overlays and meta viewport.
  • Autosizes (boosts) text for pages without a defined viewport.
select a device

Adding custom device presets

Device Mode offers a wide array of devices for emulation. You can add a custom device if you find an edge-case or niche device that isn't covered.

To add a custom device:

  1. Go to DevTools Settings.
  2. Click the Devices tab.
  3. Click Add custom device.
  4. Enter a device name, width, height, device pixel ratio, and user agent string.
  5. Click Add.

Your custom device is now available in the Device dropdown menu.

select a device

Device states and orientation

toggle orientation

When emulating a specific device, the Device Mode toolbar shows an additional control that primarily serves as a way to toggle the orientation between landscape and portrait.

On selected devices, the control does more than just orientation toggling. For supported devices like the Nexus 5X, you'll get a dropdown that allows you to emulate certain device states, like:

  • Default browser UI
  • With Chrome navigation bar
  • With opened keyboard
Change the Device UI

Zoom to fit

Sometimes you'll want to test a device that has a resolution larger than the actual available space in your browser window. In these cases, the Zoom to Fit option comes in handy:

  1. Fit to Window will automatically set the zoom level to the maximum available space.
  2. Explicit percentages are useful if you want to test DPI on images, for instance.
Zoom to Fit

Optional controls (e.g. touch, media queries, DPR)

Optional controls can be changed or enabled by clicking on the three little dots on the right side of the device toolbar. Current options include

  • User agent type (Emulates UA and touch events)
  • Device pixel ratio
  • Media Queries
  • Rulers
  • Configure Network (UA, Network Throttling)
Device Mode Settings

Read on to learn more about the specific options.

Device pixel ratio (DPR)

If you want to emulate a Retina device from a non-Retina machine or vice versa, adjust the Device pixel ratio. The device pixel ratio (DPR) is the ratio between logical pixels and physical pixels. Devices with Retina displays, such as the Nexus 6P, have higher pixel density than standard devices, which can affect the sharpness and size of visual content.

Some examples of "Device Pixel Ratio" (DPR) sensitivity on the web are:

  • CSS media queries such as:

    @media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) { ... }

  • CSS image-set rules.

  • The srcset attribute on images.

  • The window.devicePixelRatio property.

If you have a native Retina display, you'll notice that low "Dots Per Inch" (DPI) assets look pixelated while higher-DPI assets are sharp. To simulate this effect on a standard display, set the DPR to 2 and scale the viewport by zooming. A 2x asset will continue to look sharp, while a 1x one will look pixelated.

Media queries

Media queries are an essential part of responsive web design.To view the media query inspector, click Show Media queries in the three dot menu. The DevTools detect media queries in your stylesheets and display them as colored bars in the top ruler.

show media queries

media query inspector

Media queries are color-coded as follows:

Queries targeting a maximum width.
Queries targeting widths within a range.
Queries targeting a minimum width.

Quickly preview a media query

Click a media query bar to adjust the viewport size and preview styles for the targeted screen sizes.

View associated CSS

Right-click a bar to view where the media query is defined in CSS and jump to the definition in source code.

web fundamentals media queries view


Toggle this option to show pixel-based rulers next to the viewport.

Configure network (UA, network throttling)

Selecting this option opens the Network Conditions drawer, where you can change the following network behaviors:

  1. Disk Cache: Disable Disk Cache stops pages and their assets from being cached by the browser while the DevTools are open.
  2. Network Throttling: Simulate slow network connections.
  3. User Agent: Allows you to set a specific UA (User Agent) string override.


Device Mode has some limitations.

  • Device hardware
    • GPU and CPU behavior are not emulated.
  • Browser UI
    • System displays, such as the address bar, are not emulated.
    • Native displays, such as <select> elements, are not emulated as a modal list.
    • Some enhancements, such as number inputs opening a keypad, might vary from actual device behavior.
  • Browser functionality
    • WebGL operates in the emulator, but is not supported on iOS 7 devices.
    • MathML is not supported in Chrome, but is supported on iOS 7 devices.
    • HLS playback (HTTP Live Streaming for video) is not supported while emulating, but is supported natively on Android Chrome and iOS.
    • The iOS 5 orientation zoom bug is not emulated.
    • The line-height CSS property operates in the emulator, but is not supported in Opera Mini.
    • CSS rule limits, such as those in Internet Explorer, are not emulated.
  • AppCache

Despite these limitations, the Device Mode is robust enough for most tasks. When you need to test on a real device, you can use Remote Debugging for additional insight.


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