Dead Pixel Test – Check Your Screen Online
Fill your screen with solid colours to find dead and stuck pixels. Each colour reveals a different fault, so work through all six and look closely — especially near the edges, where problems cluster.
Dead pixel test
Runs in your browser. Nothing is recorded or uploaded.
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How to use this dead pixel test
- Clean your screen first with a dry microfibre cloth. Dust looks exactly like a dead pixel and is far more common.
- Darken the room if you can. Backlight problems and faint stuck pixels are much easier to see.
- Press Start test. The screen fills with white.
- Tap or press any key for the next colour. Scan slowly, row by row, about 30 cm from the screen.
- Press Esc to exit at any point.
What each colour reveals
- White — dead pixels, which stay black. Also the best screen for spotting dust and smudges.
- Black — stuck pixels lit in any colour, and backlight bleed around the edges.
- Red, green and blue — a pixel with one failed subpixel appears dark only on that colour's screen. This is how you tell a partly-failed pixel from a fully dead one.
- Grey — uneven backlighting, banding, and OLED burn-in, all of which hide on pure black or white.
What the results mean
- A black dot on white that stays black on every colour. A dead pixel. It receives no power and will not recover.
- A coloured dot on black. A stuck pixel, with one subpixel jammed on. These sometimes recover.
- A dot that is dark on red but normal on green and blue. One failed subpixel rather than a whole pixel. Less visible in ordinary use.
- Glow at the corners on black. Backlight bleed or IPS glow. Common, and only a defect when severe.
- A faint permanent image on grey. Burn-in, on an OLED panel. Not fixable, though varied content slows it.
- Something that moves or wipes away. Dust, not a fault.
Found a problem? What to do
Trying to revive a stuck pixel
- Colour cycling. Rapidly flashing colours over the affected area sometimes frees the subpixel. Leave it running for a few hours; this is the safest method and is worth trying first.
- Gentle pressure. Switch the screen off, press very lightly on the exact spot with a soft cloth, and release as you switch it back on. This occasionally works — but pressing hard can damage more pixels, so if you are not comfortable, do not.
- Know when to stop. Neither method works reliably, and neither does anything for a genuinely dead pixel. A few attempts is reasonable; an afternoon is not.
Making a warranty claim
- Look up your model's pixel policy on the manufacturer's site. The thresholds vary more than people expect, and knowing the number before you call saves an argument.
- Photograph the screen showing the fault on white and on black, with something for scale.
- Note where on the screen it is. Several manufacturers apply stricter limits to the centre than the edges.
- If you bought recently, the retailer's return window is usually a faster route than a manufacturer claim.
Checking a new or second-hand screen
- Run this test immediately on a new monitor, within the return window. Pixel faults present on arrival are far easier to resolve than ones reported months later.
- When buying second-hand, run it before paying, with the seller present.
- Check all six colours. A single-subpixel fault is invisible on most of them.
- Look at the corners specifically on black — that is where backlight bleed shows, and it is worth knowing about before you buy.
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Frequently asked questions
What is the difference between a dead pixel and a stuck pixel?
A dead pixel receives no power and stays black whatever is displayed, so it only shows against white or a light image. A stuck pixel is permanently lit in one colour — usually red, green or blue — because one subpixel is jammed on, and it shows against black. The distinction matters because stuck pixels sometimes recover, while dead ones essentially never do.
Can a stuck pixel be fixed?
Sometimes. Rapidly cycling colours in that area can unstick it, and there are tools that do this — leave one running over the spot for a few hours. Very gentle pressure with a soft cloth on a switched-off screen, released as you switch it on, also works occasionally. Neither reliably works, and pressure risks damaging more pixels, so weigh it against what you would lose. A dead pixel will not come back by any method.
How many dead pixels does a warranty cover?
This varies by manufacturer and by panel grade, and it is usually stricter than people expect. Many consumer monitors are only replaced at three to five dead pixels, and some count a bright stuck pixel more seriously than a dark dead one, or apply tighter limits near the centre of the screen. Check your model's specific pixel policy — manufacturers publish it, and the thresholds differ enough that it is worth reading rather than assuming.
I see a dark spot but it moves when I touch the screen.
Then it is dust or a smudge on the surface, not a pixel fault. A pixel fault is in the panel and cannot move. Clean with a dry microfibre cloth first, and only use a screen-safe liquid if that fails.
The edges of my screen glow on the black test. Is that a fault?
That is backlight bleed, and most LCD panels show some. It is only a defect when it is severe enough to be visible in ordinary use rather than on a full black screen in a dark room. IPS panels commonly show a similar effect at the corners, called IPS glow, which changes as you move your head — that is normal for the technology and not covered by warranty.
Does this work on an OLED or a phone screen?
Yes, and OLED screens fail differently: because each pixel makes its own light, a failed one is genuinely black and shows only against a light background. OLED also risks burn-in, which shows as a faint permanent ghost of something displayed for a long time. The grey test is the best one for spotting that.
Why does the test want to go fullscreen?
Because faults cluster at the screen edges, and browser chrome and the taskbar hide exactly that area. On a desktop you can also press F11 before starting for true fullscreen. On iPhone, Safari does not allow it, so the test runs inside the page and the edges stay covered.
How close should I look?
Close enough to see individual pixels, which on a desktop monitor is around 30 cm. Scan slowly across each colour in a row-by-row pattern rather than glancing at the whole screen — a single pixel is easy to miss. A dark room helps considerably for the black and grey tests.
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