Screen Resolution Checker
Free screen resolution checker that detects viewport size, device pixel ratio, color depth, and orientation. Live-updating with breakpoint references.
About Screen Resolution Checker
This screen resolution checker instantly detects and displays detailed information about your screen, browser viewport, and display capabilities. All values update in real time as you resize your browser window, making it an essential tool for web developers and designers.
Display Information
The tool detects your screen resolution (full display dimensions), browser viewport size (the content area inside the browser), device pixel ratio (for Retina and HiDPI displays), color depth, and screen orientation. Aspect ratios are calculated automatically for both screen and viewport.
Live Viewport Tracking
Viewport dimensions update instantly as you resize your browser window. This is invaluable for testing responsive breakpoints, as you can drag the window to the exact width you need and see the pixel value in real time without any external tools.
Resolution Comparison
The tool identifies which common resolution standard your screen matches or is closest to, such as HD (720p), Full HD (1080p), QHD (1440p), or 4K (2160p). This helps you quickly understand your display class without memorizing resolution numbers.
CSS Breakpoints Reference
A built-in reference table shows common CSS media query breakpoints used in popular frameworks and responsive design patterns. Each breakpoint is highlighted when your current viewport matches, helping you verify which breakpoints are active at any given window size.
Common Use Cases
- Testing responsive web designs at specific viewport widths
- Verifying device pixel ratio for image asset optimization
- Checking screen resolution for display troubleshooting
- Referencing CSS breakpoint values during frontend development
Working on responsive CSS? The PX to REM converter helps translate pixel breakpoints to scalable units. All detection runs entirely in your browser using standard web APIs.
Frequently Asked Questions
What is the difference between screen resolution and viewport size?
Screen resolution is the total number of physical pixels your display has (e.g., 1920x1080), while viewport size is the area inside the browser window where web content is rendered. The viewport is typically smaller because it excludes browser chrome like the address bar, tabs, and scrollbars.
What is device pixel ratio (DPR)?
Device pixel ratio is the ratio between physical pixels and CSS pixels on your display. A DPR of 2 (common on Retina displays) means each CSS pixel is rendered using 4 physical pixels (2x2). Higher DPR values result in sharper text and images but require higher-resolution assets for web content.
Why does my viewport size change when I resize the browser?
The viewport represents the visible content area of the browser window, so it changes whenever you resize, maximize, minimize, or change the browser window in any way. This tool updates the viewport dimensions in real time so you can see the exact values at any window size.
How is this tool useful for web developers?
Web developers need to know exact screen and viewport dimensions to test responsive designs, set CSS media query breakpoints, ensure proper rendering on different devices, and verify that assets are appropriately sized for various device pixel ratios. This tool provides all that information in one place.