What this tool does
The Screen Resolution Detector reads your display properties in real time and presents them in an easy-to-understand format. It shows your full screen resolution, the current browser viewport size, device pixel ratio, color depth, screen orientation, and the effective (physical) resolution your hardware actually renders. All values update live as you resize or rotate your device.
How it calculates
**Effective Resolution:** \`\`\` Effective Width = Screen Width x Device Pixel Ratio Effective Height = Screen Height x Device Pixel Ratio \`\`\` For example, a 1920 x 1080 screen with a 2x DPR (Retina display) actually renders 3840 x 2160 physical pixels.
**Aspect Ratio:** \`\`\` Aspect Ratio = Width / GCD(Width, Height) : Height / GCD(Width, Height) \`\`\` The tool reduces dimensions by their greatest common divisor, then fuzzy-matches against well-known ratios like 16:9, 4:3, and 21:9 for a clean label.
Key metrics explained
- **Screen Resolution**: Your display's full dimensions in CSS pixels, as reported by the operating system. - **Viewport Size**: The inner dimensions of the browser window, which change when you resize. - **Device Pixel Ratio (DPR)**: How many physical pixels map to one CSS pixel. A DPR of 2 means Retina or HiDPI. - **Color Depth**: Bits per pixel for color rendering. 24-bit means true color (16.7 million colors). - **Orientation**: Whether the display is in landscape or portrait mode and its rotation angle. - **Effective Resolution**: The true number of hardware pixels being rendered, calculated by multiplying screen resolution by DPR.
Who should use this
- **Web developers**: Check viewport dimensions and DPR when building responsive layouts and testing media queries. - **Designers**: Verify that assets look sharp on high-DPI displays and confirm aspect ratios for mockups. - **Gamers**: Confirm your native resolution and pixel density before adjusting in-game graphics settings. - **IT support**: Quickly identify a user's display configuration when troubleshooting layout or rendering issues. - **Anyone curious**: Find out the exact specifications of the screen you are using right now.
How to use
1. Open this tool in your browser — your display information appears automatically. 2. Resize the browser window to watch the viewport dimensions update in real time. 3. Rotate a mobile device or tablet to see the orientation value change. 4. Use the badges in the Display Summary section for a quick overview of your screen characteristics.
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