Dead Pixel Test — Check Your Screen Online
Fill your screen with solid colours to reveal dead pixels, stuck pixels, dust and backlight problems. Works on monitors, laptops, phones and tablets. Press Escape at any time to exit.
Clean your screen first — a speck of dust looks exactly like a stuck pixel.
Or jump straight to one colour
Inside the test: click or press any key for the next colour, Escape to exit.
What to look for on each colour
| Colour | What it reveals |
|---|---|
| White | Dead pixels (black dots), dust, smudges and dark patches |
| Black | Stuck pixels (bright dots), backlight bleed and IPS glow at the edges |
| Red, green, blue | Individual sub-pixel failures — a pixel may work on two colours and fail on the third |
| Grey | Banding, blotchiness and uneven brightness across the panel |
| Cyan, magenta, yellow | Combinations that make partial sub-pixel faults easier to see |
Look at the screen from straight on and about an arm's length away, then move closer. Scan systematically — left to right, top to bottom — rather than letting your eye wander, because a single pixel is easy to miss on a large display.
Dead, stuck and hot pixels
The three are often confused and they behave differently.
A dead pixel gets no signal and stays black no matter what is displayed. On a white screen it appears as a small black dot. Dead pixels are permanent; no software or massage technique recovers them, because the transistor driving the pixel has failed.
A stuck pixel is permanently on, showing red, green, blue or white against a black background. The sub-pixel is receiving constant voltage. These sometimes free themselves, especially if the fault is recent, which is why colour-cycling and gentle-pressure methods are worth trying on a stuck pixel and pointless on a dead one.
A hot pixel is a stuck pixel that only appears when the panel warms up, so it may be invisible when you first switch on and obvious after an hour. If you are checking a screen before a return window closes, run the test after the display has been on for a while.
Trying to revive a stuck pixel
Two approaches have a modest success rate and are worth attempting before accepting the fault.
The first is rapid colour cycling. Use the auto-cycle button above and leave it running for twenty minutes to an hour with the stuck pixel in view. The constant switching sometimes shifts the liquid crystal back into normal operation.
The second is gentle pressure. With the screen off, place a soft, slightly damp cloth over the pixel and press very lightly with a fingertip or a blunt, soft object, then switch the screen back on while releasing. The idea is to redistribute the liquid crystal.
Press gently. Too much pressure permanently damages an LCD and creates a much larger dark patch than the pixel you were trying to fix. If you are not comfortable, do not do it — a single stuck pixel is a far smaller problem than a pressure-damaged panel.
Backlight bleed, IPS glow and clouding
On a black screen you may notice pale glow at the corners or along an edge. This is not a pixel fault. Backlight bleed is light escaping around the edge of the panel where it is not perfectly sealed, and it shows as bright patches that stay put as you move your head. IPS glow is a silvery sheen at the corners that changes or disappears as you shift viewing angle, and it is inherent to IPS panels rather than a defect. Clouding is uneven blotchiness across a dark image, usually from uneven pressure in the panel assembly.
Some degree of all three is normal on LCDs, especially at lower price points. They become a warranty matter only when severe. OLED panels have none of these because each pixel emits its own light, but they can show other artefacts such as uneven tinting at very low brightness.
Checking a new screen before the return window closes
Run this test the day a new monitor, laptop or phone arrives. Do it in a dim room, with the display warmed up for at least half an hour, at full brightness. Photograph anything you find with the colour still on screen — a photograph with a visible defect is far more useful in a return conversation than a description. Note the position of each fault, because many warranty policies treat a defect near the centre of the screen more seriously than one in a corner.
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Dead pixel test FAQ
What is the difference between a dead pixel and a stuck pixel?
A dead pixel receives no power and stays black on every colour. A stuck pixel is permanently lit in one colour — it will show as a bright red, green or blue dot on a black screen. Stuck pixels sometimes recover; dead pixels almost never do.
How do I find them?
Run the test full screen and look carefully at each solid colour. A dead pixel is easiest to spot on white, and a stuck pixel is easiest to spot on black. Clean the screen first so dust is not mistaken for a fault.
Can a stuck pixel be fixed?
Sometimes. Rapidly cycling colours over the affected area can unstick a sub-pixel, and very gentle pressure with a soft cloth through a warm cloth occasionally works. Neither is guaranteed, and pressing hard risks making things worse.
How many dead pixels before a warranty claim?
It depends on the manufacturer and the panel class. Many warranties only replace a panel above a threshold — often several dead pixels, or one in the centre region. Check your specific policy before assuming you are covered.
What is backlight bleed and is it the same thing?
No. Backlight bleed is light leaking around the edges of an LCD, visible as glowing patches on a black screen. It is a characteristic of the panel and its assembly rather than a pixel fault, and it is common on cheaper LCDs.
Does this test work on a phone?
Yes. Open it on your phone, tap to go full screen and tap again to change colours. OLED phone screens can also show uneven patches, which is different from a pixel fault.
Check the rest of your hardware
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