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Dead Pixel Test
Flood your screen with solid colours and find any faulty pixel in under a minute.
A faulty pixel is tiny, but once you notice it you cannot unsee it. A 1080p monitor holds more than two million pixels, and every one of them is built from three subpixels: red, green and blue. When a subpixel stops responding, you get a dot that no longer matches the rest of the image. The catch is that on a photo, a web page or a game, that dot hides inside the visual noise. It only becomes obvious when the display shows one flat colour from edge to edge.
That is exactly what this test does. It fills the entire screen with pure red, green, blue, white and black, with no borders or interface to distract you. Against each background, a broken pixel gives itself away instantly as a dot of the wrong colour. The whole sweep takes less than a minute and needs nothing installed, so it is worth running the moment you unbox a monitor, a laptop or a television, and worth repeating whenever you suspect something has changed.
How to Run the Test and What It Cannot Tell You
Go full screen and step through the colours one at a time. On each background, scan the surface in sections — the centre first, then the four quadrants, then the edges — and get close, around thirty centimetres away. White and black reveal the most: dead pixels stand out against white, while stuck pixels light up against black. Before you start, wipe the panel with a dry microfibre cloth, because a speck of dust or a fingerprint is easily mistaken for a dead subpixel. The limits are worth knowing. This is a visual inspection, not a measurement. It will not tell you how many pixels are affected when several sit close together, it cannot separate a panel defect from a particle trapped under the protective glass, and on heavily matte coatings the surface grain can mask very small dots. It is also the wrong tool for whole dark lines across the screen, which usually point to a failing driver board or cable rather than individual pixels.
Types of Pixel Defect You Might Find
Not every odd dot is the same, and they do not share the same outlook. This table sums up the five possible outcomes of the test, how each one looks and how much hope there really is of fixing it.
| Type of defect | How it looks | Can it be fixed |
|---|---|---|
| Dead pixel | A black dot that stays off on every background, white included. All three subpixels have stopped receiving current. | No. The transistor is damaged and no software trick brings it back. A warranty claim is the only route. |
| Stuck pixel | A dot locked on red, green, blue, cyan, magenta or yellow. Obvious against black, invisible against its own colour. | Sometimes. Fast colour cycling, or very gentle pressure on the spot, frees it in a fair share of cases. |
| Faulty subpixel | A very small dot with a faint tint, visible only up close against white or against the complementary colour. | Rarely. It usually stays as it is, though it is subtle enough that most people stop noticing it. |
| Blotch or pressure mark | A diffuse lighter or darker area with no sharp edges, often shifting slightly when you move your head. | Not through software. This is physical damage to the panel or backlight and belongs in repair territory. |
| No defects | All five backgrounds look completely even, with no dots or local tints, both at normal distance and up close. | Nothing to fix. Run the test again now and then, especially if you carry the machine around. |
Why Checking Your Pixels Matters
The most practical reason is timing. Almost every manufacturer applies a pixel policy with a minimum threshold: they will not swap a panel over a single dark dot, only once a certain count is reached, and the criteria tend to tighten as the product tier rises. On top of that, the retailer who shipped the screen usually offers a no-questions return window that is far shorter than the manufacturer warranty. Catch the defect inside that window and you swap the unit without argument. Catch it three months later and you are in a slower process with a much thinner chance of success.
The second reason is that a stuck pixel has a treatment window. The sooner you find it, the better your odds of reviving it with colour cycling, because the liquid crystal has spent less time settled in that position. After months or years, the success rate falls off a cliff. So it pays to run the test on the same day you set the screen up, and to spend a few minutes on recovery if something shows up.
Finally there is proof. If you record one continuous video from the moment the seal is intact through to the first power-on and the backgrounds of this test, you hold a document that is hard to argue with. It is the simplest way to shut down the suggestion that the damage happened while the screen was in your hands, which comes up often when a defect resembles a pressure mark. It costs nothing and saves a lot of correspondence.
Tips to Get More Out of the Test
- Wipe the panel with dry microfibre first: half of all scares turn out to be dust rather than pixels.
- Record the unboxing as a single uncut video, from the sealed box through to first power-on and this test.
- Use moderate room lighting; in darkness the white background dazzles you and hides the smallest dots.
- Photograph the screen during the test and mark each defect, with a ruler or a reference object beside it.
- If you find a stuck pixel, run several minutes of fast colour cycling before writing it off as permanent.
- Repeat the check on new displays and after any long trip with the machine in a bag or a suitcase.
Frequently Asked Questions
What is the difference between a dead pixel and a stuck pixel?
A dead pixel receives no current and stays black no matter what, even on a white background. That is an electrical failure in the transistor driving it, and no software can undo it. A stuck pixel still receives current, but its subpixels are frozen in one position, so it always shows the same bright colour and stands out against black. The stuck one is the hopeful case: rapid colour cycling forces the liquid crystal to move and, in a fair share of cases, returns it to normal behaviour.
How many dead pixels does it take to get a monitor replaced?
It depends on the manufacturer and the product tier. Policies typically set a minimum number of bright or dark pixels, and that threshold is stricter on professional models than on entry-level ones. Some brands advertise a zero bright pixel guarantee as a selling point, and a few treat defects in the centre of the screen differently from those near the edges. Before filing anything, look up the policy for your exact model and compare it with the retailer's return terms, which are usually more generous during the first weeks.
Is it safe to try unsticking a pixel?
Colour cycling is harmless — it only changes the image very quickly. Manual massage is a different matter. If you attempt it, do it with the screen off, using a fingertip wrapped in a soft cloth and the lightest pressure you can manage, working the exact spot for a few seconds. Too much force can create permanent blotches or damage the liquid crystal layer, and that damage is not covered by any warranty. If the pixel sits in an expensive panel or the return window is still open, claiming beats gambling.
Can a dead pixel appear later in the display's life?
Yes. Panels age and transistors can fail at any point, although defects most often come from the factory and surface within the first hours of use. Sustained heat, knocks and pressure on the screen all raise the risk. That is why it is worth repeating the test occasionally, especially on hardware that travels: a laptop spending its days in a backpack alongside books faces pressures a desktop monitor never sees.
Does the test work the same on televisions and phones?
Yes, as long as you can display the colour full screen with no bars. On a television you can open this page in the set's own browser or cast it from a computer, taking care to switch off picture modes that apply enhancement or local dimming, since they can distort what you see. On a phone, the sheer pixel density makes a faulty subpixel nearly impossible to spot with the naked eye, so a close-up photo taken with another device often helps.