Samsung Galaxy S21: CSS viewport of 360 × 800 px, resolution and responsive test

Why test your site on Samsung Galaxy S21?

CSS viewport resolution of Samsung Galaxy S21

This is the resolution that interests designers and developers the most, as it determines breakpoints and the definition of media queries. In practice, it's the only one mentioned in a stylesheet.

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 Samsung Galaxy S21

The device pixel ratio of Samsung Galaxy S21 is 3. In other words, a 1-pixel square in CSS occupies 3 pixels on the panel. An image exported at actual size will appear blurry.

Manufacturer resolution of Samsung Galaxy S21

This resolution is the hardware's. It explains the display's sharpness, but it's never the one to target in a media query.

• 1080 pixels in width
• 2400 pixels in height
• 424 pixels per inch (ppi)
• 6.2 inches diagonal, or 15.8 cm
• Screen ratio of 20:9

Media queries and code snippets for Samsung Galaxy S21

These snippets are generated from the exact characteristics of Samsung Galaxy S21. Copy them directly into your stylesheet or configuration.

@media only screen and (min-width: 360px) and (max-width: 799px) {
  /* Samsung Galaxy S21 */
}

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

// tailwind.config.js
module.exports = {
  theme: {
    screens: {
      'samsung-galaxy-s21': '360px'
    }
  }
}

const isDeviceWidth = window.matchMedia('(min-width: 360px)').matches;
const isHighDensity = window.devicePixelRatio >= 3;

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

Free Samsung Galaxy S21 simulator

Mobile FIRST includes Samsung Galaxy S21: your page displays in a viewport of 360 x 800 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 Samsung Galaxy S21 — Select Samsung Galaxy S21 from the list of devices. The viewport switches to 360 x 800 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.

Models sharing the format of Samsung Galaxy S21

These 4 devices share exactly the viewport of 360 x 800 pixels and the 3x density of Samsung Galaxy S21. Their CSS rendering is therefore exactly the same: what you validate on one is valid on all others.

• Samsung Galaxy S20
• Samsung Galaxy S21+
• Xiaomi 12 2022
• Xiaomi Mi 11i

Comparison with similar models

The neighboring formats of Samsung Galaxy S21 are the ones to test right after, as they reveal poorly placed breakpoints.

Frequently asked questions about Samsung Galaxy S21

Updated on August 15, 2026