The quick check
Clean the screen, set brightness high, start the full screen test and step through every color. Look across the whole panel from normal viewing distance first, then from closer, section by section. A faulty pixel is a sharp dot that stays in exactly the same place on every color where it is visible. Dust and smudges look softer and move when you wipe.
Each type of fault hides on some colors, so do not stop after black and white. The test on this page cycles through nine colors: black, white, red, green, blue, cyan, magenta, yellow and gray. Click, press space or the right arrow for the next color, use the left arrow or right click to go back, and press Esc to finish.
Try it here: Dead Pixel Test
Open the full tool pageDead, stuck and hot pixels
Each pixel on an LCD or OLED screen is made of three subpixels: red, green and blue. They mix to every other color. The kind of fault depends on which subpixels are stuck on or off.
| Fault | What you see | Easiest to see on | Can it recover? |
|---|---|---|---|
| Dead pixel | A black or dark dot that never lights | White, then gray | Rarely |
| Stuck pixel | A dot fixed in red, green, blue or a mix such as cyan or yellow | Black and the other colors | Sometimes |
| Hot pixel | A dot that is always white or very bright | Black | Rarely |
| Dead subpixel | One color missing, for example a cyan dot on white because red is off | White | Rarely |
| Dust or debris | A soft, slightly blurry speck | White | Wipe it off |
Step by step on different devices
Monitor or laptop: open the test in your browser, start it, and the page switches to full screen and hides the cursor. Check every color, and on a laptop also tilt the lid to rule out reflections. Use the native resolution so one dot on screen is one real pixel.
TV: open the page in the TV's built in browser, or connect a laptop by HDMI and run the test full screen. Turn off picture modes that sharpen or smooth the image, because some processing can hide single pixels. Walk up close: on a 65 inch 4K TV each pixel is about 0.37 mm wide, so a fault is invisible from the sofa but clear at arm's length.
Phone or tablet: open the page in the browser, turn brightness to maximum and start the test. Tap to move to the next color. A magnifying glass or the zoom of a second phone's camera helps on dense screens.
For a new screen, also look at black in a dark room. Light patches near the edges of an LCD are backlight bleed; a glow that changes when you move your head is IPS glow and is normal. OLED screens have no backlight, so pure black should be completely dark.
What return policies usually cover
Policies differ by manufacturer, model and country, so read the warranty terms for your exact screen. In general, many manufacturers accept a small number of faulty pixels as within specification, often with stricter limits for bright (hot or stuck) pixels than for dark ones, and stricter limits near the center of the screen. Some premium lines promise zero bright pixels. These rules are often based on the pixel fault classes of the ISO 9241-307 standard.
The shop you bought from is usually the easier route. Many retailers accept returns within a fixed period, commonly 14 to 30 days, and in the EU most online purchases can be returned within 14 days without giving a reason. That is why the test belongs on day one. If you find a fault, take a photo with the test color on screen and note the position, then contact the seller before the period ends.
Safe ways to try fixing a stuck pixel
Stuck pixels sometimes free themselves after a few hours or days of normal use, so wait before doing anything risky. Dead and hot pixels usually mean a failed transistor and rarely come back.
The gentle pressure method: turn the screen off, fold a soft microfiber cloth, and press lightly with a fingertip or the rounded end of a stylus on the spot for a few seconds, then turn the screen on and check. Press only lightly. Hard pressure can damage more pixels, and on many laptops and phones it can crack the panel. Never use pens, sharp objects or heat.
Some websites and videos flash colors very quickly to exercise a stuck pixel. Results are mixed, and rapid flashing can trigger seizures in people with photosensitive epilepsy, which is why this site does not offer it. If you try one, do not watch the screen while it runs, keep the area small and stop if anyone nearby feels unwell.
Common mistakes during the test
- Testing only on black or only on white: stuck pixels hide on some colors and dead ones on others.
- Low brightness: dark dots are much harder to see when the backlight is dim.
- A scaled resolution: if the computer is not at the panel's native resolution, one faulty pixel may look blurred.
- Confusing dust with a fault: wipe the screen and check again; a real fault does not move.
- Waiting too long: by the time you notice a dot while working, the return window may have closed.
What a single pixel means in practice
On a 27 inch 4K monitor there are more than 8 million pixels, and each one is about 0.16 mm wide. A single dark pixel near the edge is often invisible in daily use, while a bright one in the center of a monitor used for dark games or photo editing can be distracting every day. Decide based on where it is and how you use the screen, not only on whether it meets the policy.