How the dead pixel test works
Press Start the test and your screen fills with solid red. Look over the whole screen, then press the right arrow key, the space bar or tap to move on: green, blue, white, black, then a gradient and a grid. The left arrow goes back, and Esc leaves. Each screen only changes when you ask, so take your time.
Clean the screen first, so you don't mistake a speck of dust for a pixel. Sit at your usual distance and scan it in sections, left to right. A magnifying glass or your phone's camera zoom helps on a high resolution screen. Nothing is uploaded.
Dead, stuck or hot: what you are looking for
Every pixel is made of three subpixels, red, green and blue. Mixing them makes every color you see. A bad pixel is one where some of them no longer do what they are told:
- Dead pixel: always black. You see it best on white and on the bright colors.
- Stuck pixel: always one color, often red, green or blue. It stands out on screens of a different color, and on black.
- Hot pixel: always lit white or bright. It shows best on black.
That is why the test runs through all three primaries plus white and black: each one hides some faults and shows others. A pixel that looks wrong on every screen is the one to note down.
The gradient and the grid
The gradient fades from black to white. It should look smooth; visible bands or steps are banding, which is common on cheaper panels and on some color settings. The grid checks sharpness and geometry: lines should be crisp and straight right out to the corners. Blurry lines at your screen's native resolution usually mean scaling is on somewhere.
On black, also look at the edges in a dark room. Light leaking in along the sides is backlight bleed. The black screen page explains how to tell it apart from normal IPS glow.
Found a bad pixel? What to do
- Check the return window. A new monitor bought recently can usually go back to the store, which is often simpler than a warranty claim.
- Read the pixel policy. Many makers publish how many bad pixels it takes before they replace a screen, and it varies by brand and model. Some cover even a single bright pixel; others need several.
- Take a photo. A close-up of the pixel on the screen where it shows best helps a claim.
You will find videos and pages that flash colors quickly to "unstick" a pixel, or advice to press on the spot with a cloth. There is no good evidence that flashing fixes stuck pixels; some people report it helped, which may be a pixel that would have recovered anyway. It can't bring back a dead pixel, and pressing on a panel can damage it. We don't offer a flashing tool, partly for that reason and partly because fast flashing is a risk for people with photosensitive epilepsy.
While you are setting up a screen, it is worth getting its height and angle right. The monitor arm finder sorts arms by screen size, weight and how they mount.
Questions
How do I know if I have a dead pixel?
Run the test and look for a dot that stays black on the white and colored screens. If it stays one color instead, it is a stuck pixel.
Can dead pixels spread?
Usually not. One bad pixel doesn't damage its neighbors. If you see more appearing over time, or a line of them, that points to a different fault and is worth a warranty claim.
Does this work on phones, laptops and TVs?
Yes, on anything with a browser. On a TV, open the page in its browser or cast a browser tab to it. On an iPhone, Safari keeps its own bars on screen, so check the edges separately.
Is this test safe for people with photosensitivity?
The colors never change on their own and never flash; each change needs a key press or a tap. They are bright and saturated, though, so lower the brightness first if bright color bothers you, and skip the test if it can trigger a seizure.
What's the difference from the white and black screens?
The white screen and black screen show one color for as long as you like. This test walks you through every color and pattern you need for a full check, in order.