Detect actual screen resolution, pixel density (DPI/PPI), viewport dimensions, device pixel ratio, and color depth. Verify display specifications and test responsive design breakpoints. Essential for web developers and UI designers.
Device pixel ratio (DPR) determines how many physical pixels represent one CSS pixel. High-DPI displays (Retina, 4K) have DPR of 2 or higher, meaning they render more pixels for sharper images. This tester reveals your display's actual pixel density and how it affects web rendering.
Start with the live tester below. Supporting details, FAQs, and troubleshooting guidance are placed after the tool so the main action is easier to find and use immediately.
Detect actual screen resolution, pixel density, and viewport dimensions.
Common problems
If the live tester does not behave as expected, these are the first checks most users should try before assuming the hardware is broken.
Check actual vs reported resolution
Verify pixel density (DPI/PPI)
Test device pixel ratio
Check viewport dimensions
Detect actual screen resolution, pixel density (DPI/PPI), viewport dimensions, device pixel ratio, and color depth. Verify display specifications and test responsive design breakpoints. Essential for web developers and UI designers.
Device pixel ratio (DPR) determines how many physical pixels represent one CSS pixel. High-DPI displays (Retina, 4K) have DPR of 2 or higher, meaning they render more pixels for sharper images. This tester reveals your display's actual pixel density and how it affects web rendering.
Test your keyboard input, detect dead keys, and verify all keys are working correctly.
Test mouse buttons, scroll wheel, pointer tracking, and touch input.
Test your microphone input levels in real-time. Verify microphone is working.
Test your speakers or headphones with reference tones.
Helpful questions
Use these answers to understand results, browser limitations, permissions, and sensible next troubleshooting steps.
Open the live screen resolution test on this page and follow the prompts shown in the tester area. The tool runs directly in your browser, so you can check your device without installing additional desktop software or signing in.
Check browser permissions, confirm the device or browser feature is enabled, and reload the page if needed. Many browser-based testers depend on permission prompts, secure context support, or hardware access that must be approved before the test can run fully.
Web development - ensure responsive design works. It can help you confirm whether the issue is caused by the hardware itself, a browser permission setting, or a system configuration problem before you spend more time debugging.