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Kordu Tools

Dead Pixel Test

Test your monitor for dead or stuck pixels with fullscreen solid colours. Includes a stuck pixel fixer that rapidly cycles colours to revive unresponsive pixels.

How It Works

This test fills your screen with solid colours so you can inspect for defective pixels. A dead pixel stays black on every colour. A stuck pixel shows the same colour regardless of background. Use the fullscreen test to cycle through each colour, then try the pixel fixer if you find a stuck pixel.

Test Colours

Stuck Pixel Fixer

Rapidly flashes colours to help unstick a stuck pixel. Position the flashing square over the affected pixel for best results.

100 x 100

How to use

  1. 1

    Launch the fullscreen test

    Click 'Start Fullscreen Test' or select a specific colour to begin. Your screen will fill with a solid colour.

  2. 2

    Inspect each colour

    Click anywhere or press any key to cycle through black, white, red, green, blue, and grey. Look carefully for pixels that do not match the background.

  3. 3

    Identify pixel issues

    A dead pixel stays black on every colour. A stuck pixel shows the same colour regardless of the background. Note the location of any defective pixels.

  4. 4

    Run the stuck pixel fixer

    If you find a stuck pixel, exit the colour test and activate the Stuck Pixel Fixer. Position it over the affected area and run it for five to ten minutes to attempt recovery.

Frequently asked questions

What is a dead pixel?
A dead pixel is a pixel on your display that has permanently failed and appears as a tiny black dot regardless of what colour the screen is showing. Dead pixels are usually caused by manufacturing defects or physical damage and cannot be fixed with software.
What is a stuck pixel?
A stuck pixel is a pixel that displays one colour continuously — often red, green, or blue — instead of changing with the rest of the screen. Unlike dead pixels, stuck pixels can sometimes be fixed by rapidly cycling the colours they display.
Does the stuck pixel fixer actually work?
It works in some cases. Rapidly cycling colours can help a stuck transistor reset itself. Success depends on the cause — newer stuck pixels are more likely to respond. Running the fixer for five to ten minutes gives the best chance.
Does this tool need to be downloaded or installed?
No. The tool runs entirely in your browser using the Fullscreen API. Nothing is downloaded and no data leaves your device.
Which browsers support the fullscreen test?
All modern browsers — Chrome, Firefox, Edge, Safari, and Opera — support the Fullscreen API. On mobile devices, the test works but is most useful on larger desktop or laptop monitors where individual pixels are easier to inspect.

Check your monitor for dead, stuck, or hot pixels with this free online

screen test. Cycle through fullscreen solid colours — black, white, red,

green, blue, and grey — to spot any pixel that fails to display correctly.

A dead pixel stays black regardless of colour, while a stuck pixel shows

one colour permanently. If you find a stuck pixel, activate the built-in

pixel fixer, which rapidly flashes colours in a targeted area to help

unstick it. Everything runs entirely in your browser using the Fullscreen

API — no downloads, installs, or data collection.

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