Background
Dead, stuck, and hot pixels explained
A 4K monitor has 8,294,400 pixels, and each one is built from three subpixels: red, green, and blue. That is almost 25 million tiny light valves or emitters that all have to work. When one of them fails, the result is a dot that ignores what the screen is supposed to show. The color of that dot tells you a lot about what went wrong.
Three kinds of pixel fault
On an LCD, every subpixel is switched by its own thin-film transistor (TFT). The backlight is always on behind the panel, and the liquid crystal over each subpixel decides how much of that light gets through. On an OLED, each subpixel produces its own light. In both cases a fault shows up as a point that stays the same while everything around it changes.
- Dead pixel: stays black on every background. All of its subpixels are off. It is easiest to see on a white screen.
- Stuck pixel: stays red, green, blue, or a mix such as yellow or magenta. One or two subpixels are stuck on or off. It shows best on a background of a different color, for example a green dot on black or red.
- Hot (bright) pixel: stays white or very bright on every background. All three subpixels are stuck on. It shows best on black.
- Subpixel fault: only one of the three subpixels is affected. Up close it looks like a tiny colored dot, and at normal viewing distance it can be hard to see.
Rule out dust and content first
Many reported dead pixels are dust on the screen surface or a speck trapped in a screen protector. Dust usually looks slightly blurred, sits on top of the image, and can cast a faint shadow when you look from an angle. A pixel fault is sharp, sits in the image plane, and stays exactly one pixel wide.
A dot can also be part of the content. If you take a screenshot and the dot appears in the screenshot, it is coming from the computer, not the panel. If you move a window over the spot and the dot moves with the window, it is in the image, not the screen.
Can a stuck pixel be fixed?
A dead pixel, where the transistor or emitter has failed, almost never comes back. A stuck pixel sometimes recovers, especially if it appeared recently. Some stuck subpixels return to normal after hours of ordinary varied content. Tools that flash rapidly changing colors over the spot are also widely used. Results are inconsistent, and rapidly flashing images are not safe for people with photosensitive epilepsy.
Pressing or rubbing the panel is often suggested online, but it can damage the liquid crystal layer or the touch layer and may void the warranty. If the pixel matters for a return or warranty claim, document it before you try anything.
How many bad pixels are “allowed”?
There is no single rule. The old ISO 13406-2 standard defined pixel fault classes. Its widely quoted Class II allowed up to two always-lit pixels, two always-dark pixels, and five faulty subpixels per million pixels. ISO 9241-307 replaced that standard in 2008, but many manufacturers still write their own pixel policies.
Today, policies differ by brand, product line, region, and seller. Some premium lines promise zero bright pixels, others count defects by type and position, and a retailer’s return window can be easier to use than any pixel policy. Check the exact document for your model before you count, and note whether a fault is bright or dark. Policies usually treat those two separately.
| Resolution | Pixels | Subpixels |
|---|---|---|
| 1920 × 1080 (Full HD) | 2,073,600 | 6,220,800 |
| 2560 × 1440 (QHD) | 3,686,400 | 11,059,200 |
| 3840 × 2160 (4K UHD) | 8,294,400 | 24,883,200 |
Common questions
- Can a dead pixel spread to nearby pixels?
- A single failed pixel normally stays a single pixel. New faults that keep appearing, a growing cluster, or a whole line of pixels point to a different problem, such as a failing driver circuit or ribbon cable. Report those to the manufacturer as soon as you notice them.
- Which background color should I use?
- Use all of them. Dead pixels show best on white, hot pixels on black, and stuck pixels on a primary color that differs from the stuck one. That is why the test cycles through white, black, red, green, blue, and their mixes.
- Will a dead pixel show up in a screenshot?
- No. A screenshot saves the image the computer rendered, and a panel fault is not part of that image. To show the fault to support, photograph the screen with a camera: one close shot of the dot and one wide shot that shows where it is on the panel.
- Do OLED screens get dead pixels too?
- Yes. OLED subpixels can fail or stay lit just like LCD subpixels. Because an OLED pixel that is off emits no light at all, a dead OLED pixel on a white background looks like a very dark point.