Xiaomi 17 Ultra: CSS viewport of 400 × 869 px, resolution and responsive test

Xiaomi · Android 16.0 · Smartphone · 2026

Released in 2026, Xiaomi 17 Ultra features a CSS viewport of 400 x 869 pixels. Here are all its display characteristics and how to check the responsive rendering of your site on this model.

Test your site on Xiaomi 17 Ultra directly in your browser, without buying the device.

  • Xiaomi 17 Ultra available in the device list
  • Real viewport, User-Agent, and touch events
  • Also works on localhost and in pre-production
  • Exportable screenshots and videos
Install for Chrome

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Why test your site on Xiaomi 17 Ultra?

3x density

Each CSS pixel of Xiaomi 17 Ultra is rendered by 3 physical pixels. Any image, icon, or font provided in simple resolution appears immediately blurry.

Very elongated screen

With a ratio of 19.5:9, Xiaomi 17 Ultra displays a lot of height for little width. Sections designed in landscape become endless columns, and full-screen visuals are poorly cropped.

Actual media queries

The 400 x 869 pixels viewport of Xiaomi 17 Ultra rarely matches the round breakpoints of frameworks. It is precisely between these values that layouts break.

CSS viewport resolution of Xiaomi 17 Ultra

This resolution is what your stylesheet actually manipulates. It determines the applied breakpoint, the number of displayed columns, and the size of your images.

  • 400 pixels in width
  • 869 pixels in height

The height remains indicative: Safari, Chrome, and other mobile browsers reduce the visible area with their address bar, which folds on scroll.

Be cautious when analyzing your statistics: some tools only report the manufacturer resolution, never the CSS viewport presented here.

Pixel density of Xiaomi 17 Ultra

3

The device pixel ratio of Xiaomi 17 Ultra is 3.

Each CSS pixel is thus rendered by 3 physical pixels, making any image provided in simple resolution immediately visible.

Manufacturer resolution of Xiaomi 17 Ultra

This is the number of physical pixels on the screen, as announced by the manufacturer. Useful for preparing your image exports, useless for your media queries.

  • 1200 pixels in width
  • 2608 pixels in height
  • 19.5:9 Screen ratio

416 pixels per inch (ppi) · 6.9 inches diagonal, or 17.5 cm

User-Agent of Xiaomi 17 Ultra

This string is what the browser of Xiaomi 17 Ultra sends. It is useful for your automated tests, reading your server logs, and server-side detection.

User-Agent

User-Agent string used by Xiaomi 17 Ultra, useful for your automated tests and logs.

Mozilla/5.0 (Linux; Android 16; Xiaomi 17 Ultra) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.6778.260 Mobile Safari/537.36

Media queries and code snippets for Xiaomi 17 Ultra

These snippets are generated from the exact characteristics of Xiaomi 17 Ultra. Copy them directly into your stylesheet or configuration.

CSS media query

Targets screens whose width matches that of Xiaomi 17 Ultra and models of the same format.

@media only screen and (min-width: 400px) and (max-width: 868px) {
  /* Xiaomi 17 Ultra */
}

Density media query

Serves high-resolution images to screens of at least 3x.

@media only screen and (-webkit-min-device-pixel-ratio: 3),
       only screen and (min-resolution: 288dpi) {
  /* High-density images and icons */
}

Tailwind configuration

Adds a named breakpoint at the exact width of Xiaomi 17 Ultra.

// tailwind.config.js
module.exports = {
  theme: {
    screens: {
      'xiaomi-17-ultra-2026': '400px'
    }
  }
}

JavaScript detection

Detects format and density client-side.

const isDeviceWidth = window.matchMedia('(min-width: 400px)').matches;
const isHighDensity = window.devicePixelRatio >= 3;

Meta viewport tag

Essential for Xiaomi 17 Ultra to use its CSS viewport and not a simulated width of 980 pixels.

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

Free Xiaomi 17 Ultra simulator

Mobile FIRST includes Xiaomi 17 Ultra: your page displays in a viewport of 400 x 869 pixels, with the model's User-Agent, touch events, and scrolling behavior of a real mobile.

This is where the difference with Chrome DevTools' responsive mode is seen: DevTools resizes a window, the extension replicates the device's browser and allows exporting shareable screenshots and videos.

  1. 01 Install the extension Add Mobile FIRST to Chrome, Firefox, or Edge. Installation is free and requires no account.
  2. 02 Open the page to test Go to the URL to check, including a local address like localhost:3000.
  3. 03 Choose Xiaomi 17 Ultra Select Xiaomi 17 Ultra from the list of devices. The viewport switches to 400 x 869 pixels, and the mobile User-Agent is applied.
  4. 04 Check rendering Scroll, change orientation, test your forms, then capture an image or video to share.

Comparison with similar models

The neighboring formats of Xiaomi 17 Ultra are the ones to test right after, as they reveal poorly placed breakpoints.

Comparison of resolutions of Xiaomi 17 Ultra and nearby models
Model CSS Viewport Pixel density Manufacturer resolution
Xiaomi 17 Ultra 400 x 869 3x 1200 x 2608
Apple iPhone 18 PRO 402 x 873 3x 1206 x 2619
Apple iPhone 17 PRO 402 x 873 3x 1206 x 2622
Apple iPhone 17 402 x 874 3x 1206 x 2622
Xiaomi 17 406 x 885 3x 1220 x 2656
Xiaomi 17T 423 x 919 3x 1268 x 2756
Xiaomi 17T Pro 427 x 924 3x 1280 x 2772

Frequently asked questions about Xiaomi 17 Ultra

What is the CSS viewport resolution of Xiaomi 17 Ultra?

The CSS viewport of Xiaomi 17 Ultra measures 400 pixels wide and 869 pixels high. This is the width to use for defining your media queries, not the manufacturer's resolution.

What is the pixel density of Xiaomi 17 Ultra?

The device pixel ratio of Xiaomi 17 Ultra is 3. Each CSS pixel is thus displayed by 3 physical pixels, requiring you to provide your images in 3x to keep them sharp.

What is the screen resolution of Xiaomi 17 Ultra?

The panel of Xiaomi 17 Ultra displays 1200 x 2608 physical pixels. This is the value reported by most analytics tools, while your CSS works on a viewport of 400 x 869 pixels.

What is the User-Agent of Xiaomi 17 Ultra?

The User-Agent of Xiaomi 17 Ultra is: Mozilla/5.0 (Linux; Android 16; Xiaomi 17 Ultra) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.6778.260 Mobile Safari/537.36

How to test my site on Xiaomi 17 Ultra without the device?

Install the Mobile FIRST extension on Chrome, Firefox, or Edge, then select Xiaomi 17 Ultra. Your page displays in a viewport of 400 x 869 pixels with the corresponding mobile User-Agent, in two clicks and for free.

What is the difference with Chrome DevTools' responsive mode?

DevTools resizes the window and applies partial emulation. Mobile FIRST additionally applies the User-Agent of Xiaomi 17 Ultra, touch events, scroll behavior, and the actual appearance of the device, and allows capturing directly usable images and videos.

Can I test a localhost address on Xiaomi 17 Ultra?

Yes. The extension works on any URL open in your browser, including localhost:3000, 127.0.0.1, or a password-protected pre-production environment.

Do you need to buy a Xiaomi 17 Ultra to test your site?

No. The simulation covers the vast majority of development needs at no cost. A final test on a cloud-hosted device is still recommended before critical production deployment, but it's no longer necessary for each iteration.

Which media query to use to target Xiaomi 17 Ultra?

A media query on the exact width targets Xiaomi 17 Ultra: @media only screen and (min-width: 400px). Combine it with the pixel density to precisely target this model and those sharing its format.

Continue testing on another model

All Xiaomi resolutions → All devices →

Other Xiaomi models

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Without buying a single phone, without creating an account.

  • 97 devices available upon installation
  • Real viewport, User-Agent, and touch events
  • Also works on localhost and in pre-production
  • Exportable screenshots and videos
Install for Chrome

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