Screen Test
Inspect your display resolution, pixel ratio, orientation, and colour depth, then run full-screen dead-pixel and gradient patterns.
Test interface
Your browser may ask for permission after you press Start.Test patterns
Use the test patterns to look for dead pixels, banding, uneven backlighting and colour problems. Press Escape to leave full-screen mode.
How to use this tool
- Read the reported screen and viewport values.
- Use the test patterns to inspect for stuck or dead pixels.
- Press Escape to leave a full-screen pattern.
- Optional: start a screen recording, capture a short clip, and stop it to release the capture.
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Technical explanation
The page reads window.screen properties and visualViewport dimensions. CSS pixels differ from physical pixels, so devicePixelRatio is shown separately. Browser privacy protections may reduce precision or hide values.
Dead-pixel patterns are solid colours that make defective subpixels easier to see. A screen recording captures the browser compositor output, not the physical panel.
Troubleshooting
Resolution looks lower than expected
Browser zoom, display scaling, and privacy protections affect reported CSS values. Physical resolution may not be exposed.
Full-screen does not open
The Fullscreen API requires a user gesture and may be blocked by embedded browsers.
Screen recording is unavailable
Some browsers or managed devices disable getDisplayMedia.
Colours look inaccurate
Colour profiles and HDR modes affect rendering. This tool cannot calibrate a display.
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Frequently asked questions
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