Dead pixel test
Inspect your display for dark or continuously lit pixels using solid colors, with optional alignment and sharpness patterns. Open the page on the monitor you want to inspect, then enter fullscreen if supported. Use the grid and geometric patterns to look for incomplete edges, distorted circles or blurred fine lines.
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Test setup
Screen preview
Ready. Choose a pattern or enter fullscreen to inspect the display.
White
Visual inspection only. The browser cannot see or count physical pixel defects.
- Browser test area (CSS pixels)
- Browser pixel ratio
Sources
- EIZO — monitor test patterns and visual inspectionSources reviewed: 2026-10-31
- MDN — fullscreen browser behaviorSources reviewed: 2026-10-31
- MDN — CSS pixels and browser scalingSources reviewed: 2026-10-31
How it works
- Compare black, white and primary-color fields.
- Inspect the same point across several patterns.
- Use the grid to check edges, circles and fine lines.
Assumptions and limitations
This is a manual visual inspection, not an automatic fault detector or repair tool. Browser color management, zoom, operating-system scaling and panel settings affect the image. The page displays patterns but cannot observe the light emitted by your physical screen.
How to use this tool
Prepare the display
Open the page on the monitor you want to inspect, then enter fullscreen if supported. Check the screen for dirt and follow its manufacturer's cleaning guidance. Use your normal viewing position and a comfortable brightness. Start at 100% browser zoom and confirm the display mode in the operating system before assessing fine patterns.
Interpret a persistent dot
A bright point on black can indicate a continuously lit subpixel, while a dark point on white can indicate a pixel that does not light as expected. Compare the same location on red, green and blue. Dirt can also appear as a dark mark, so confirm the observation before treating it as a panel fault.
Check alignment and sharpness
Use the grid and geometric patterns to look for incomplete edges, distorted circles or blurred fine lines. These are visual checks, not automatic calibration. Screen dimensions reported by a browser use CSS pixels; zoom and device-pixel ratio affect their mapping to the display. A narrow line therefore is not guaranteed to occupy one physical pixel.
Worked examples
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Check a bright dot on a new display
Start on black and note the position of the dot. Switch to white, red, green and blue. Check the same position on every field. If the dot stays bright on black, repeat the check with the monitor’s own test if available.
A persistent point is worth checking across patterns
Frequently asked questions
Can this fix a stuck or dead pixel?
No. The tool provides inspection patterns and does not repair panel hardware. If a point persists across colors, repeat the check with the monitor's built-in diagnostics or follow the manufacturer's support guidance.
Does a visible dot mean the monitor fails?
This page does not assign a pass/fail grade or a defect allowance. Confirm what you see under normal conditions; any applicable acceptance or warranty criteria come from the monitor manufacturer.
Processing and privacy
The calculation or transformation runs in your browser. The tool does not send its input values or generated output to an application server. Loading a page still makes infrastructure requests; optional analytics and Google consent messages have separate controls.
Privacy Policy. Privacy & preferences in the footer controls optional analytics.
Help and feedback
Consult the linked sources for definitions and reference data. Contact Support if you have a question or notice a problem.
Read about calculation methods · Report a problem to emonster
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