Dead Pixel Test
Show full-screen solid colours to check your monitor or phone screen for dead, stuck, or discoloured pixels.
Test interface
Your browser may ask for permission after you press Start.How to use this tool
- Clean the screen first so dust is not mistaken for a pixel fault.
- Click Start full-screen test and allow full screen if the browser asks.
- Step through white, black, red, green, blue, and grey fields using the buttons or arrow keys.
- Press Escape or click Exit when finished, and note the position of any suspicious pixel.
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Technical explanation
Each pattern is a solid CSS colour covering the viewport. A dead pixel stays black on every colour; a stuck pixel shows one colour permanently; a discoloured subpixel looks tinted. Because the page only draws colour, you are the detector — a browser cannot photograph the physical panel.
Full-screen mode hides browser chrome so it cannot hide a small defect near the edge. The browser compositor still renders the page, so this is not a hardware-level panel test. Very small or dim defects may only be visible on specific colours.
Troubleshooting
A spot looks black on every colour
Confirm it is not dust or a watermark by cleaning the screen and moving the window. A defect that stays in the same physical position is likely a dead pixel.
Full screen does not open
The Fullscreen API needs a user gesture and may be blocked in embedded browsers. Use the large colour buttons without full screen.
The whole screen looks tinted
Check night light, colour filters, HDR mode, and the monitor colour profile before assuming a panel fault.
A pixel changes colour with viewing angle
That is usually normal panel behaviour, not a dead pixel. Compare with a plain white field from directly in front.
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Frequently asked questions
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