Dead Pixel Test

Fill your whole screen with one solid colour at a time to spot dead, stuck or hot pixels. Nothing to install and nothing uploaded.

Press Start to begin.

  1. Black
  2. White
  3. Red
  4. Green
  5. Blue
  6. Grey

Fill the whole screen with each colour and look closely. A dead pixel stays black on every colour but black; a stuck or hot pixel stays one colour (often red, green, blue or white). Turn the brightness up, wipe the screen with a soft dry cloth first (dust looks like a pixel but moves), and use a dark room for the black screen. Colours change no faster than once a second in automatic mode.

🔒 Runs entirely in your browser — nothing you type is uploaded or stored on a server.

Press Start and the page fills the whole screen with solid black. Click, press Space or the right arrow to move through white, red, green, blue and grey, and look for any dot that does not match the rest. The left arrow goes back one colour, and Esc ends the test. A short caption at the bottom names the colour and fades after three seconds so it does not hide a pixel.

Also on Txtset: test your keyboard keys too.

A dead pixel never lights, so it shows as a black dot on every colour but black. A stuck or hot pixel is always on, so it shows as a bright dot of one colour on a screen of another. That is why the test needs all six colours: a pixel stuck on red is invisible on the red screen and obvious on black. Look from close up, with the brightness turned up, and use the black screen in a dim room.

If you would rather not touch the keys, tick Change colour automatically and choose how many seconds each colour stays (1 to 30; the default is 3). On a phone, where full-screen mode is sometimes refused, the page covers the screen with its own full-window layer instead and asks you to rotate the phone and hide the toolbars.

There is deliberately no “pixel fixer” here: those pages flash colours many times a second, which is a seizure risk for some people and rarely repairs anything. See the questions below.

How to use

  1. Wipe the screen with a soft, dry cloth and turn the brightness up.
  2. Press Start the test. The screen turns black.
  3. Press Space, the right arrow or click for the next colour, or tick the automatic option first. Look over the whole screen for dots that differ from their neighbours.
  4. Press Esc to stop. The line under the button says how many of the six colours you looked at.

Examples

A black dot on the white screen
Almost certainly a dead pixel. Check that it is still there on the other colours.
A bright dot on the black screen
A stuck or hot pixel. Note which colour it is on the red, green and blue screens.
A speck that moves when you wipe
Dust or lint, not a pixel.
A faint patch on the white or grey screen
Uneven backlight or panel tint rather than a single pixel. It will be visible on the grey screen.

Frequently asked questions

What is the difference between a dead, stuck and hot pixel?
A dead pixel has no power and stays black. A stuck pixel has one of its red, green and blue parts permanently on, so it shows as a coloured dot. A hot pixel is stuck on white. All three are one tiny point; a larger patch is usually a fault in the panel or its backlight.
Why six colours?
Each colour exercises different parts of every pixel. Black shows pixels stuck on, white shows pixels that never light, and the red, green and blue screens show a single sub-pixel that is stuck or dead. Grey is the easiest place to see uneven brightness and patches.
Is it a dead pixel or just dust?
Clean the screen with a soft, dry microfibre cloth and check again. Dust, a crumb or a smudge sits on top of the glass and moves or disappears. A pixel fault stays exactly where it is and is the same on every screen it should show.
Can this page fix a stuck pixel?
No, and it deliberately does not try. “Pixel fixers” flash colours many times a second. Content that flashes more than three times a second is a known trigger for photosensitive seizures (it is the limit in WCAG 2.3.1), and there is little evidence the flashing repairs a pixel. If a stuck pixel bothers you, check your manufacturer’s dead-pixel policy and warranty: many set out how many faulty pixels qualify for a repair or replacement.
How fast do the colours change?
In automatic mode each colour stays for 3 seconds by default, and you cannot choose less than 1 second. If you step through by hand, the page ignores key presses and clicks that arrive less than a third of a second after the last one, and ignores a held-down key, so the screen cannot strobe.
Does it work on a phone or tablet?
Yes. Browsers that allow full screen use it; where they do not (iPhone Safari is the usual one) the page covers the whole window instead. Rotate the phone and hide the toolbars by scrolling or adding the page to your home screen so that no part of the display is covered, then tap to change colour.
Will it find problems on an OLED screen?
It will find dead and stuck pixels. It does not measure burn-in or uneven wear, but a grey screen shows them to the eye. On OLED, each black pixel is off, so look at the black screen in a dim room.
How do I get out of full screen?
Press Esc, or use the Exit button at the bottom (move the mouse or tap to bring it back). Pressing Tab also puts focus on the Exit button.
Is anything uploaded?
No. The page only paints colours. Nothing about your screen, your device or what you saw is sent anywhere or stored.

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